I was hoping somebody could tell me which downpipe and high flow cat they like best for use with an HKS Carbon-Ti Cat-back. (eg. which ones fit, why you like what you do, etc.) I'd like to stay away from test pipes to keep emissions legal. Thanks in advance.

 

I've been looking at the Perrin 3" and the UR 3" High flow cat.

bump

 

Fitment is irrelevant. Everything fits together. Just get whatever fits and costs the least.

 

ok, that's good to know, I didn't know if different manufactures had different flanges and what not. Does it make much difference with 2.5" or 3"?