i have a mac o/r PC and mac chambered mufflers and it sounds bad as hell. thats that. Who ever said that prochamber has a raspy sound needs their ears checked. An X pipe has rasp, heck compared to a Prochamber a H pipe has rasp. My car does idle rather quite compared to other setups but i think with lts and eventually cams a prochamber can create the pinicle of mustang exhaust notes. Oh yeah if you can go catless! you pick up like 2000 dB that way.