Ok, Ive had a cgc high flow done, sydney kid helped me out big time, i got the stage 1 rebuild, (450HP), its a great turbo, they machined about 8mm out of it/ i was runnin a minimum of 12psi and max 20psi, not laggy at all!! full boost by 3500rpm, if your not goin to put an aftermarket manifold on the cgc option is awesome, highly recommened!!!!!