I have the Invidia exhaust currently which i LOVE, however it's 2.25 and I was wondering if I need to upgrade to a 3in exhaust or if that will work without too much restriction, again I love the look of my exhaust, big twin cans with blue tips, not crazy about a single but if it makes power I will live with it

 

I know that with any turbo setup the larger (3") and less restrictive (single) exhausts are the best to improve flow and get the most power wise, but if you are only going with a moderate turbo setup then you should be fine. With my VERY restrictive HKS exhaust I was able to put down 330whp @ 6psi so you should be fine with your invidia. With that being said, after the turbo I can't even hear my exhaust anymore, it now sounds almost completely stock until I floor it so I have a 3" single on order. Just keep in mind that your invidia will get much quieter with a turbo acting as another muffler.

 

good info to have thanks, I'm going to run a test pipe on it so that should free it up a bit, just out of curiosity though what kind of gains do you expect with the 3in single?

 

gains are all relative to your tune. IMHO, it's kinda silly to run an NA exhaust with a turbo. It's ok with a blower, because you are still utilizing a header, but when you taper down the DP to fit a cat or TP, you are just putting another bottle neck in the system. besides, you may like the sound of your invidia, but I'd bet you'd like the sound of a 3" DP back single too...