My friend in his 03' wrx got an greddy evo catback, sounds great. I mean you can tell its aftermarket by looking at it (oh really i didn't know the huge GREDDY logo gave that away) but its reeeeeaaalll quiet. It seems to be loudest at idle and you cant tell its on there without looking at it. I hope it sounds the same way on our cars I would love it to be like his.