I have an HKS axle back on the car now but I don't like the way it looks. I reached out to UEF and they can make me a catback that looks more stock from the back with a resonator and muffler so it isn't too loud. I mentioned that I was interested in my exhaust having some pops and gurgles and he suggested I get the 2.25" instead of the 2". Would this hurt the performance without a tune? I am thinking with the resonator and muffler it should provide enough back pressure but I wanted to ask here before ordering.

Down the road I plan to get an unequal length header but that's probably way down the road.

 

Hi I had almost the same conversation with UEH team. They are great and get back to you quickly. Quick recap, I have a 2018 EX that I have made mods to including the full HFP suspension and an HKS axle back.
With that, I have settled on full length header with high flow cat; I really wanted the Subaru burble from the unequal length, but settled on the performance from the full length. Also, the full cat back 2.0 pipe with resonator so I stay compliant with Md laws. Hope that helps.

 

For popo's related reasons i took off my Tanabe Medallion axle back and went another route... But i used 2¼" piping...

I used 2008 CiViC Si big resonator (2¼" also) and a 2012 CiViC Si muffler which is also 2¼"....

Yes it might not be the prettiest one, but it flows beautifully and it almost sounds like a CiViC Si😈..... And it feels awesome performance wise... I have to Dyno the GK since i also did a intake and IM mod and it triggers the running lean code every now and then....


So to answer your question....

YES you can go 2¼ without any issues

 

I run stock mid pipe,rv6 catted header, with no muffler and it works great. You get all the gurgle and pops lol.

 

I work as a courier so I'm trying to keep my car from getting too loud just to keep it relatively professional. Hence the reason I'm holding off on headers for now. The HKS is good, I don't want to get too much louder.

 

I decided im selling my Hks Hi flow axel back muffler.

 

The header and axle back alone won't be loud with the stock mid pipe.... Since it's between 1¾...and 1⅞..... Really really small....

 

Then it sounds like I would be better off getting the catback for now and getting the header down the road. That way I will get rid of the donut gasket.