i'm running a 00 civic greddy kit 5psi. will the turbo spool faster witha fast flow cat or is not worth it buying one for now. i have evo exaust too.

 

if you are running 2.5 inch dp and evo exhaust the stock cat is a restriction. go to http://www.mufflertech.com for at least a 2.5 inch carsound cat. is the greddy dp even 2.5 inch? i'd bump up that in size too. the evo is not truely a 2.5 inch exhaust either. i'm thinking of changing my exhaust, but it's good for now.