I put an X pipe on my gtx with headers, 2 1/2" pipes and the giant 20" case dynomax super turbos and my exhaust is WAY quieter than I thought it would be. I haven't really driven it yet, but at idle and free reving it I am very pleased with the sound. This is on a stock 70 440 with an MP resto magnum cam.
Travis..


70 GTX project, orig 440-4, 4 spd, track pack, FC7, stripper/street racer special.