Well, I have put Eibach Sport springs on my Accord Coupe and it really changed the way the car handles. I also have Honda 17's and Proxes T4 tires @ 215-50's if I remember correctly.
My blue FIT is really stiff probably because of the 21mm front lower anti-sway bar and torshion rear suspension. I really like the way the stock suspension works as I can take corners as well as my lowered Accord.
I bought the basic FIT and have only added the 195 55 X 15's with Dunlops and FIT Sport wheels. My son (works for Honda dealer) got me the above take-off's at a good price.... no NOT the $86 per tire and $365 per wheel. Much less, but I can't tell
Anything larger than a 16 or 17 would be much too much and @ 17's you are limited here in the US at performance tires only... at least what I can afford. As it is the Proxes only last about 25000! And even at dealer cost they are expensive.
I use the car for fun driving, utility (I surprise everyone with what can be FIT in the back), mpg and around town. And I am finding that I am neglecting my MODified Accord. But it is a much more powerful car with great (32mpg) highway milage even @ 85 mph.