Porting and T6's is fine, it's the port timing that hurts them. Toomeys fit better, sound better (both sound similar), and they have a great rep for backing they're pipes. My friend got a set of CPI's in the mail and started to polish them before we put them on and the chrome came off! They exchanged them and now O.K. but I never heard of toomey's doing that. Both are good pipes, I'm not knocking CPI, just look around and make your own decision.