Hello Wanderer,

Yes Ohlins in Japan made a kit called BTO (Built To Order)
for Honda Fit GE
here is the link:
???? BTO?????????|???????? ???????????????[ÖHLINS Advanced Suspension Technology]
just click on the Fit after you go to the above links.

I almost going to buy this Ohlins coil over kit,
but then I see their spring rate and then
I see that for the Ohlins price,
I can buy Bilstein plus I also have (a lot of) extra money left to help me buy my JDM RS Complete Rear Axle with Disk Brake conversion.
so I decided not to buy the Ohlins.

The list price is 271,000 yen, but you can get them for a bit less
from some Rakuten vendor.

You see, I after looks not performance, because I am old now hahaha
and for looks, it is easier for people to spot my rear disk brake then
for people to spot an Ohlins inside the fender...
unless, I put BIG OHLINS STICKER on my windows to advertise that I am using Ohlins hahaha

hey, I am NOT a hypocrite, I buy stuff for my car for looks only not performance... well ok, I want performance too but not looking for ultimate performance, just better performance (read: reliable) with ultimate looks...

If my car is going too fast, nobody can notice it anyway...
hahaha I am such a poser... well again I am old now (really I am old),
so the day for me driving fast is over...
(unless if someday I can afford a GT3 RS (RS as in Rennsport) not a FIT RS (RS as in RoadSailing), hahaha then I might going fast again) hahaha

 

Of course using a zip tie to secure an ABS sensor line is a cost cutting method in production. I would expect that on something like a Megan Racing, CX or other CHEAP type of kit. But on Bil$tien'$? That's just cutting corners. So what if it costs the consumer anther $25 for a proper bracket? If your already paying $1K+ you should be able to expect better in my opinion.

Progress rate springs for street.

As a concept, I understand that.... I just can't support progressive rate springs...

They do not behave consistently. Therefore, at the limit (Say a PANIC braking or collision avoidance maneuver) you cannot always predict how they will react.

The real point of a coil over is to offer adjustable spring load, spring perch height, steering geometry alterations and usually a major bump in both dampening and spring rate.

If you want to "go lower," and maintain a "comfortable ride" then either do it on the Swift lowering springs which are intended to match the OE dampers OR just buy a set of "Basic" coil overs like the ones being re-offered by T1R. https://www.fitfreak.net/forums/aj-r...1r-basics.html
Cheap, with reliable build quality and plenty of "low" possible. There are numerous reviews on here of people who got them the first time around.

No one will know the difference between the $$$$ Bil$tien'$ and the $$$ T1R and either one will let you ruin your front lip and fenders.

 

I am slightly puzzled by the use of progressive springs on adjustable coilovers, soft linear springs 2.5-5k ride really comfortably if you have the dampers dialed in.

I am wondering if it is to prevent the shock from bottoming (higher rate at high compression?) and blowing? Is that a problem with linear springs with rates that low? I've used lower rate springs 4-6k before and never bottomed out (no bumpstops!) but am not sure...

 

oh come on,
using a tie lock works fine.
if you buy some REAL racing suspension and put it on some WRC rally car
or DTM car, that suspension most likely do NOT have a welded brake line bracket too and you can use zip ties to secure the brake line (or of course
you could make your own custom bracket)...

Also you say that:
They do not behave consistently. Therefore, at the limit (Say a PANIC braking or collision avoidance maneuver) you cannot always predict how they will react.

I had owned both car with linear spring suspension and progressive suspension and when you are doing panic braking on the street,
they both react well or better than stock suspension.

Let's use Bilstein for example,
even if Bilstein spring is progressive but their softest rate were already harder then the factory honda stock spring rate.
so when you press your brake, initially they will lean less then the factory spring but then harden up more compare to factory spring.
although not as hard as Koni's linear spring.
so in this case alone, Bilstein will have better performance then factory spring.
For collision avoidance manuver,
again same thing.
with factory spring soft rate, your car will lean more initially and keep on leaning more after that...
while with Bilstein it will lean less then factory spring in initial response,
but will later even less lean than factory because it is harder (progressive).
and yes again, the koni's linear and MUCH HARDER spring rate will lean less from the beginning compare to Bilstein.
But on real street application it is better to have a bit softer suspension,
so you won't skip over bump especially in the initial movement.
if you have harder linear spring and you go over a bump on the road
while cornering hard (or emergency manuver),
you could end up skipping the bump because the suspension
is too hard.
as you said above and I read here, some people use Bilstein on their track car and before this Koni's kit came up,
everybody never complain about Bilstein with progressive spring being dangerous/unpredictable on panic braking/avoidance manuver which should happened a lot on the track...

but sure, the Koni's linear spring (and MUCH HARDER RATE) on race track (which most likely smooth track surface)
will have a better time compare to the Bilstein,
but on real street application (lot of potholes, bumped uneven pavement, half concrete half asphalt freeway,
it will not make a different.

what you will notice right away is how much harder the car will be with that Koni linear spring.

if you buy the Swift with stock spring, then it will let you lower your car,
but will not let you adjust the lowering height.
beside the stock shocks is build for much softer and taller stock spring.
while the swift is shorter and also harder, so no matter what,
the stock shocks will not have enough damping power for that harder swift spring. Yes, Swift claim their spring will work with the stock shock...
of course it will, but is it optimal?
and if it is optimal with stock shocks, how come it is even better if you use
Swift with the harder damping Koni's shock? that alone show that
the stock shock is actually not a good match to swift spring.
Heck, even with stock spring I can feel that the stock shocks do not have
enough damping power.

Bilstein stock is 100% suitable for their own progressive spring.

if you buy T1-R (which is currently offered at much lower price then they use to be), as good as they are,
they were not backed by a big company for future warranty.
I mean, tuner came and go, but Bilstein had been around for many years (like Koni) and I don't think they will close soon.

Beside,
if someone ask you, what your suspension is,
and you say, I use Bilstein,
it had that extra "cachet" compare if you say I use T1-R.
if you know what I mean

of course, if you say I use Ohlins, well that is even better

Look, Koni's kit from Chris is most likely going to be a good suspension
for the track, and good value for the money.
but for daily street use,
I think nothing beat the comfort/performance, value, brand cachet, height adjust ability of Bilstein.
At TireRack it is only $1,130,
Koni's from Chris is around $200 more.

last thing you say:
No one will know the difference between the $$$$ Bil$tien'$ and the $$$ T1R and either one will let you ruin your front lip and fenders.

but when they drive in on the street, people whenever driver or passenger will notice that the Bilstein is MORE COMFORTABLE then the Koni's,
I mean Spring Rate doesn't lie !
and if you say Bilstein will ruin your front lip and fenders,
well Koni's would do the same too with same lowered height right?so my point is,
it all depend on budget.

if you have limited budget and want just lowered looks for streets,
then go with Swift Spring or Eibach Spring or other spring.

if you have more budget and can afford some coil over for streets,
but you also want more performance and comfort than springs only,
then you can buy T1R or other cheaper brand,
if you also care about reliability and warranty backed by large manufacturer then you buy Bilstein.

(with the current T1R lowered price and the current Bilstein price, you can
already see that the buyer of this 2 coil over will came from different market segment, after all the Bilstein cost almost 2 times the current
lowered T1R price, so people who want Bilstein will still buy Bilstein,
and people who usually want more affordable coil over now have another choice to choose with is T1R).

if you have limited budget and want to get the coil over for track use
with sacrifice in street comfort then buy Koni, I really think it is a great
value for the money.

if you have unlimited budget and going to use it for track use,
and don't care about street comfort and only want the ultimate track comfort you can buy Ohlins or other expensive suspension available out there.

of course, if you have unlimited budget and want it to have the ultimate track looks, then there is nothing wrong of buying Ohlins...
I really almost buy Ohlins, until I realize it is too expensive,
and it is also too hard for daily use...
If I am driving a GT3 RS then ok, I don't mind the hard suspension,
but I am driving a Fit who with Ohlins will ride as hard as a Porsche...
hmmm....

no matter what people say that Koni will be comfortable for street use,
well that LINEAR spring rate number doesn't lie. it will never be as comfortable as Bilstein. (yes this despite the monoshock tube vs dual tube design).

but again no matter what people say how good Bilstein progressive spring is at the track, again spring rate will not lie, and on this one I am pretty sure Koni's will be better on the track !

Final note, if you are going to use your car for street use only,
when you buy your coilover,
are you prepared to have your car ride stiff all day long? (read: ride stiff on the straight and during cornering).
if you are ready for that, go with Koni's
if not then progressive spring will suit you better (be it just lowering springs or other coilover out there).

 

Ok, from the Bilstein spec their progressive spring rate is
from around 2 to 4k, so it is comfortable (at 2) and harder at 4 (when lean more).

but a "soft" linear spring rate will have a FIX rate,
either 2.5 all day long
or 3 or 4 or 5 all day long.
if you use 2.5 linear spring, well it is soft but then the car will lean more then the bilstein during hard cornering/hard braking
if you use 5 linear spring, well that number don't lie,
and a harder spring will NO DOUBT result in harder ride.

from what I understand (correct me if I am wrong) from what Chris told us on the forum,
the linear spring need to be harder because the way their coil is wound,
they can NOT have as much travel (compress) as progressive spring,
so if they compress too much with soft rate, that linear spring will break (or deform)
that is why they need to be harder to limit the range of travel.

you say you use lower spring rate at 4 to 6k range.
I assume this is linear right?
of course it will never bottom up,
because that spring rate is very high and it ride harder which mean almost no chance of bottoming up
with stock Fit weight no matter how hard you corner or brake (not counting during accident of course).

I mean the factory spring rate which most likely less than 2k is easier to
bottom up because it is soft,
but if you manage to make your 4 to 6k linear spring bottom up, well before they bottom up, they (the spring not the shock) might had break into pieces first or they will DEFORM.

again, correct me if I am wrong about this...

 

OP: So I have based ALL of my replies on that.

Yes, I race my Fit AND Daily Drive it with my 8K/10K race suspension. NO I don't expect every one to do so.

I am only here expressing my opinions, and it seems they differ from yours, not the end of the world.

I am heavily performance biased.

Some food for thought. The following is the results from our most recent event. The 3rd column is a raw time, and the 4th is indexed by the class factor (class is 2nd column):


You'll notice my <$20K New, "Econo Box" is less then 6/10ths of a second raw time off a "GT3." Index timed for class, well....

 

well it depend on the track and it depend on the team and it depend on who is driving the car.

if you have Factory Porsche Driver driving the GT3 against
Factory Honda Driver driving the Honda Fit on International Race Track
(not small track with too many small corner) then there is no way
a Honda Fit can compete against a GT3. (Indexed or not) unless you use some crazy index algorithm.

I mean why did the Nissan have to use their Nissan GT-R with factory nisan driver on the Nurburgring, to win against the Porsche's (or Ferrari's),
why don't Nissan just use their small Nissan Versa ?

Yes, you have a good time, I am sure you are a good track driver,
and your skill enable you to have a better time compare to that GT3
in the latest event that you enter.
but if you really enter proper racing, on a proper sanction track,
do you really think you can win in a Honda Fit against an equally good driver in a Porsche GT3?

now back to topic,

do the starter of this thread (the prospective buyer of the suspension for his/her Honda Fit) want their Honda Fit to ride as hard as a Porsche?

if yes, then Koni will be a good choice.

 

Yes, I suppose "comfort" is relative. 4-6k is still "soft" relatively to me anyway, those rates still allow for quite a bit of body roll and suspension compliance with bumps, or so has been my experience. But anyway...

Are OEM springs not linear though? And have low rates?

Bump stops prevent the springs from bottoming out the shock at full compression, but I don't think the springs would fail?

 

Yes, at first that puzzle me too,
why stock spring with linear and softer spring rate do NOT break?
but I think it is because
the stock spring is much taller (the way they wound the coil)
so it have more range of usable travel built in..
compare to the Koni's (or is it eibach or swift) linear spring...
again correct me if I am wrong...

The first time I know that linear (non factory) spring need to have harder spring rate was from Chris on one of his post at this Koni's thread.

 

I don't think they've been back since they started this thread, hopefully they return, cause this is a great discussion!

Alpina what do you think of the other Koni set ups

 

missed that ninja edit...

 

Ok here is (again):
Bilstein B14 Spring rate are:
Front Spring 2.6-4.2kgf/mm (progressive)
Rear Spring 2.4kgf/mm

now, I am really confused (and right now too lazy to find out)
what unit did the Koni's rate are using. it is metric or imperial...
or nm...
anyway assume it is metric,
so lets start using the standard best spring rate recommended
by Chris which is:
Standard Best Spring Rates: 300/275

and Bilstein: roughly around 260 to 420nm front and 240nm rear...
again this is roughly and I think it is not exacly 2.6kgf/mm equal 260nm...
but just say roughly...

that mean initially the Bilstein front spring rate is softer than the
Koni's but at full lean the Bilstein will be harder then the Konis.
while at the rear, the Konis spring rate are always harder than the Bilstein.

but of course we already know the above easily... just by looking at the number...

the main different here is again as TPColgett said is
LINEARITY...
during a full attack track session, you would want a suspension
that is as predictable as possible in extreme maneuver and at the limit,
while at street, you are not suppose to drive at the limit (legally).

this is similar to why Normally Aspirated car is easier to drive at the track
because the power delivery is linear,
while the Turbo charged car (at least some earlier one), have sudden jump or non linearity on the power delivery which make it driver harder
because you always had to compensate of that sudden non linearity...

so if you want to go to the track,
I think Koni is the better one for sure due to it's linearity.

also notice that on the more oriented Koni track set up,
it had more harder spring rate at the BACK then the front !!!

I also remember that Chris insist he would love to have double
Progressive sway bar at the rear of his car if he has time
to make a bracket for it. That mean Chris as skilled driver
like to have that oversteer handling and ability to move the back around.

well, I guess the racer would prefer Oversteer handling...

but on street use, unless you are really skilled driver,
I don't think you want an Oversteer handling car.
(or if your car sometimes be driven by your girlfriend or wife,
who I assume most wife and girlfriend is not a racing car driver )
that is why Chris also offer the street setup with harder front spring rate.
(understeer)...

that is what I personally think...

 

Chris's rates are in pounds per inch. I'll re read above and edit this further later when not tired and in a poor mood.

 

Ok, Thanks TPC,
so
since Chris rate are lb/in and using this website which have online converter:
Spring Rate Converter

Koni:
Standard Best Spring Rates: 300/275 (lb/in) = 5.36/4.91 (kgf/mm)

Street Comfort: 300F/200R (lb/in) = 5.36/3.57 (kgf/mm)

Street/track (fun): 350F/400R (lb/in) = 6.25/7.14 (kgf/mm)

Street/track (advanced): 400F/550R (lb/in) = 7.14/9.82 (kgf/mm)

so this Koni spring rate is SIGNIFICANTLY harder then Bilstein.
Even the Koni Standard Package is much harder then Bilstein's spring progressive rate at it's maximum rate.
so for sure Bilstein will be the more comfortable suspension here...

Don't forget that Bilstein spring rate is already HARDER then Swift and MUGEN Coil Over,
so I think for street use (within legal limit) that is already hard enough.

Bilstein B14 Spring rate are:
Front Spring 2.6-4.2kgf/mm (progressive)
Rear Spring 2.4kgf/mm

The Koni's 4 spring rate choice are also much harder than SWIFT spring
(SWIFT spring rate data taken from Chris website) 129F/117R (lb/in) = 2.3/2.1 (kgf/mm)

Hey, it is interesting that SWIFT Spring front spring rate is just little bit less then Bilstein front spring rate at it's minimum rate
and also the same for the rear spring of both SWIFT and Bilstein...
also no wonder SWIFT spring do not have too much drop because they are linear spring and their spring rate are not hard too,
so they can not go too low.
Lot of people say SWIFT spring ride is comfortable yet the handling is good.
and Bilstein with slightly harder spring rate compare to SWIFT will surely ride a bit stiffer then the swift/stock shock combo
but since the shocks from Bilstein had better damping characteristic compare to stock shocks/swift spring combo,
that could be the reason the Bilstein is still a comfortable coil over plus can drop further than the swift.
although the response will not be as linear as SWIFT of course... but no matter how linear the swift spring is,
I think the stock shock will be the limiting factor for the swift here...

at least that is what I see from reading the number on spring rate between the Bilstein, Swift and the 4 package spring from Chris Koni...

The beauty of Koni is they can be revalve right?
how much will it cost to revalve it?,
and how much will it cost to buy another spring if you decide to move to higher spring rate?
how much will it cost for taking out and installing the suspension again (if you had shop do it for you),
and how much will it cost for doing alignment again?
so unless you are going to different track requiring different setup, the adjustability of the Koni for using different spring rate
will not be utilize and might be cost prohibited... just changing spring rate and revalve (if needed) will cost at least $500 above
depend on whether you install/uninstall the suspension your self and depend on where you do your alignment.

This mean despite adjustability of Koni, you still have to pay if you want to change later...
so it is best to make sure you know what spring rate you want from the beginning so you don't have to spend money later if you want to buy Koni.
another good info from Chris website:

Reference Data: Stock spring rates on 2009+ Fit are
95 lb*in front and 112 lb*in rear or
1.7kgf/mm front and 2kgf/mm rear.

which mean the SOFTEST Koni's package is around 3 times harder at the front and almost 2 times harder at the rear compare
to stock spring

while the HARDEST Koni's package is around more than 3.5 times harder at the front and a whooping 5times harder at the rear compare to stock spring.

This is some serious suspension and spring rate for sure !

Do the starter of this thread want that kind of harder suspension? I think he do want it if he is planning to use the car at track but if he plan it strictly for street use?

yes, buying Bilstein mean you are STUCK with NON ADJUSTABLE Spring rate suspension, but do you really want to change your spring rate down the road?
if you do, then Koni is the way to go.
if not, STUCK with Bilstein is not bad either.

 

I also keep hearing that since Koni's is adjustable
so when you want to ride your car on your way back home from track,
you can just adjust the coil over rebound knob and it will be street comfortable again...

now after doing all this discussion on this thread I suddenly realize that
this Koni strut package is the Single Adjustable REBOUND only package.

but the compression is NOT adjustable
which mean when you hit a BUMP,
it will still feel the same whether you had that rebound knob on the minimum or maximum.
unless if there is a multiple bounce on the row which mean if you put the rebound to minimum
it will allow the spring extend back to it's original length ready to absorb another upcoming bump,
but this also mean the car will be more bouncy...

so how come it will became more comfortable when it is not COMPRESSION adjustable ?

yes, the rebound setting is great for the track use so you can adjust the bounciness of your car,
but on street
with the hard spring rate and non adjustable compression Koni,
you will still always feel the same over bump no matter how you change your rebound regardless you
are on the road or on the track.

remember Chris told us that this Koni is good because even though it is only 1 way rebound adjustable,
the rebound adjuster does not connected to the compression adjustment... and that is the correct way.
so the compression remain constant no matter how you adjust the rebound.
otherwise if you put the rebound harder, it will make the compression too hard.

so the point that this Koni can be adjusted to be soft on the street
and hard on the track using rebound adjustment were NOT correct.
Unless you upgrade the shock to the koni racing 2 way adjustable shocks...
on this standard koni kit, the hardness will always remain constant no matter you adjust your rebound.

the only advantage over Bilstein (for damping) is the rebound adjustability which
is great for setting up the car bounciness in specific track use but much less important in how comfortable the ride is.

and of course that advantage of the LINEARITY of the spring from Koni's kit, which again more beneficial for track use.

oh, one more advantage, but this one for street use...
if I am not mistaken this Koni can be lowered much more than Bilstein without effecting
the damping characteristic,... right?
so yes, another advantage of Koni is it can go lower then Bilstein,
and when you go lower, I think you will need the harder spring rate from this Koni so you wont easily scrape your bottom
on dip at road...

 

Work has been crazy so I just now had a chance to get back to this. Great discussion and insight. Based on what I've seen so far I'm strongly leaning towards the Bilstiens. I like the idea of the adjustability of the Koni's but the reality is this car will never see the track. I'm looking for something that will firm up stock and provide a more enjoyable ride without causing my wife to complain about the car if she is in it.

That said, don't let this finish the discussion. It's been very enlightening.

 

Yeah, that's correct about the drops... just didn't wanna bring up a moar low conversation... lol.
Koni 1"-3" (25.4mm-76.2mm)lower
Bilstein ~.79"-~1.97" (20mm-50mm) lower

 

You would think this to be true wouldn't you? It is not. Rebound has more to do with ride comfort than you would intuitively think. Reducing the rebound allows the car and shock to FLOAT after a bump, so while the inital bump might be slightly harsh, any bumps following will be soaked up by the shock extending slowly. If the shock extends quickly in a short period of time, you will experience the same harsh bump again (think expansion joints or grooves in bridges). Allowing the shock to float is terrible for performance but good for comfort. This is why a lot of companies do not put a compression adjustment on entry-level coilovers.

Here is a good link to be read, good synopsis of suspension:
http://hondaworkshop.com/misc/bathroom_tuner.htm

Ultimately, spring rate has the most to do with the comfort. I think if you have shocks that are set up to control the springs, and a rate that is not excessive, you can make a street car more than comfortable with rates around 4 to 5k.

Also as I said before, "comfort" is subjective.

 

 

This is what said on the website that you point out about rebound:
Too much rebound force

• Wheels do not return quickly to road surface after displacement. Inside wheel in a corner may be pulled off the road by the damper while still loaded
• Car may 'jack down' over bumps or in long corners causing a loss of tyre compliance. Car does not power down well at exit of corners when road surface is not extremely smooth

Too little rebound force: overall

• Car floats - oscillates after bumps (the Cadillac ride syndrome)

and this is about Compression:
Too much shock: overall

• A very sudden car with harsh ride qualities, much sliding and wheel patter
• Car will not absorb road surface irregularities but crashes over the

Too much bump force: general

• Harsh reaction to road surface irregularities.
• Car slides rather than sticking
• Car doesn't put power down well - driving wheels hop.

Too little bump force: overall

• Initial turn in reaction soft and sloppy
• Excessive and quick roll, dive and squat

so based on the website that you point out it is clear that the word "soft", Comfort, ride quality is related more toward compression than rebound.


as I stated in my previous post, if you have too much rebound and you drive over series of bump in succession, the suspension will bottom out because the spring do not have enough time to extend.


so basically on the track you would want extra rebound to control the body movement more, but on the street you want less rebound.
still if you buy Bilstein, they already have the ideal rebound for street use
and their rebound power should be much less than the Koni who already have much higher spring rate than the Bilstein.


If you go all out on the track, the Bilstein might not have enough rebound power but again the Bilstein spring also is not that hard in the beginning.


ok, let me put it in more simple word.


if you have True Racing Double adjustable Koni Shock (Rebound and Compression Knob).
Which Knob between Rebound and Compression would allow you to feel the most different in Ride Quality if you turn it...


Do you feel the ride stiffen up more if you turn up the rebound or

Do you feel the ride stiffen up more if you turn up the compression ?


of course you will feel right away that the ride become more STIFF (not comfortable) if you dial UP the compression knob.


so the compression is the one which is more important (DIRECTLY RELATED) for ride comfort
compare to rebound.


the rebound knob will have the indirect effect toward comfort but if people expect that if they use Koni and turn down the rebound to minimum
on their way back from track and that can suddenly make their car behave like Bilstein (comfort), well they will be disappointed.


As you said comfort is a matter of taste,
but number don't lie.
You have to use the Fit STANDARD spring rate as base line.
then compare how many times more stiff do you want your car on the road.

Do you really want it to be 2 times stiffer or 3 times or 4 times stiffer? that
is why the spring rate is stated on the spec so before they buy, they can guess
how much stiffer their car will be with that spring rate on that coil over.

People who track their car had a need to stiffer spring and since they are used to "track car ride" they begin to be immune from harsh ride thus
they think it is still comfortable


but for ordinary people who don't track their car,
they would be in for a surprise if they buy Koni because it is much more harder/stiffer compare to stock.


and when they then turn down their rebound knob thinking that it will make their ride very comfy... again they will be surprise because
the ride is still hard and actually if you turn down the rebound adjustment on this koni to minimum the ride than maybe became floaty because not enough rebound power for that high spring rate.


Lot of people out there do not know how to set up their car suspension,
and once they learn that the rebound knob do not help with the harsh/stiff ride, they will be disappointed and start saying bad things about their Koni. this is not good.


in summary, rebound knob set up to minimum for this Koni would NOT
help with ride.
remember this spring rate is LINEAR, so if you hit first bump (same size bump), the spring will compress with same rate, and then if you hit the second bump right away, the spring will compress further but still at the same rate so the harsness is still going to be the same...
but if you have to much rebound than soon the suspension will compress to it's maximum travel range and the shock hit bump stop and then when
it start to be rock solid (no suspension).
but even if you adjust the rebound to a minimum and let the spring get back to it's initial position before the second bump, that first and second bump will still feel HARD the same because Koni have the LINEAR spring rate...
so this show the rebound knob do not help in adjusting the comfort
but it's more to control the body movement, control the suspension from bottoming out too.


if you read again the website you point out,
there is NO reference toward comfort on rebound adjustment, it only talk about the Floaty feeling which is not related to comfort but more toward the way the car handle. so even that website support that comfort is DIRECTLY related to Compression.


as you said, the harsh/stiffness ultimately came from spring,

Spring work when it receive COMPRESSION,
and the shocks also have some Compression added,
so if you dial the compression up, it will add more stiffness thus harsh ride
and vice versa
This mean unless you use the dual adjustable Koni with compression adjustment, the ride will be the same all day long.
of course the HANDLING will be different when you adjust the REBOUND knob, but
the Ride Harshness/stiffness will remain CONSTANT if you do NOT have the Compression Knob adjuster.