ok well ive searched and havnt really found a straight answer id like to get some ideas from u guys based upon my setup...98 civic ex greddy sohc kit at stock boost 5psi.

currently im running a stock *** exhaust n stock cat... now what do u guys think i should do? 2.25 or 2.5 is there really gona be a huge difference? most boost ill probably go for is 7 or 8psi not anytime soon also throwin in a high flow carsound cat.

2.25 cuz i know the greddy dp is 2.25 i duno wat difference it makes if the piping after that is anybiger...
im thinkin a magnaflow exhaust..what do you guys think?

 

not really sure on an answer for you but i am going to be doing 2.5in piping with a highflow cat with the greddy kit at 9psi. I dont think it will make a difference at low boost but if you dicide to up it later 2.5 would prolly meet your needs better.

 

2.5 inch atleast. I kept stock cat and went with a Magnaflow 2.5" straight threw muffler. **** is nice and mellow at high rpm and real quiet when im not getting on it.

 

Greddy DP is 2.25? i thought it was smaller Anyways 2.5 at the smallest...3 couldn't hurt

 

crap its even smaller!? anyway eh6turbo where did you get your exhaust from? ive been lookin for a 2.5 magnaflow, am i going to be feeling a nice noticable diff when i switch over from my stock exhaust?

 

Contact h-t user KTeller8. He sells custom exausts for specific cars. That's where I got my piping and then I just grabbed a 2.5" Magnaflow Oval off ebay for like 50 shipped brand new. And you will definately feel a difference. From what I hear the 2" piping stock restricts flow greatly. I personally wouldn't know cause I ran open downpipe when I installed my turbo until the exaust shop could do my shiznit. Good luck with the project. If you need anymore help you can pm me or IM me on AIM at hxcadam