Ok i need some help....everyone keeps telling me taht the best exahust for my turbo gsr is 3" all the way back....but i talked to an exhaust guy the other night and he said that since my Downpipe is only 2 1/2" that my exhaust should be the same and i wouldnt be gaining any power or loosing any power with a bigger exhaust....someone please help me....he was alos concerned that the 3" exhaust wouldnt make ground clearence or make it past my rear suspension....THANKS.....basically will a 2 1/2" exhaust be fine for my turbo car????