i have them on a 2000 gt and it sounds wicked. i also have a bassani catted x-pipe. wanted a muffler no one else had so i thought id try them. i had turndowns made for the cutouts. i have had a bunch of mustang guys listen to the car and they all really liked the sound. it will sound like no other 4.6. these mufflers w/ the stock h pipe were louder than my 95 with an offroad h pipe and 2 chamber flows.