if u get a high flow cat like a real high flow cat and now one of those 3 dollar ones on ebay u should be ok. i think magnaflow makes one that people like. but like bigpoppahutrm said its gonna cost u a lot and u might wanna think about a test pipe(which is pretty much what those ebay ones are lol) and an O2 simulator or something, thats what most people do. just my though