I had a set of custom pipes made for my 04 2.3. they put a 9 inch muffler (cherry bomb) and 3 inch magnaflow tips. they bolt right up to the stock Y pipe at the rear of the car. Ok here's the question I can tell the car launches better off the line and climbs through the gears faster ........but at 105mph its done no more speed. stock muffler slower through the gears but higher top end speed . Why is that?