they do! i tested out the system last night ( had a header leak the first fire up and major timing issues) and it sounds BRUTAL! at idle, it is very very deep (the dumps do help), but once you rev it up the x-pipe really comes to life and the engine just barks...sounds real intimidating, it is exactly the sound i was after...and oh, its definatly louder than a super 40 car:toothy10:
next rainy day im gonna get some pics and vid up as right now im using all the good weather to finish off some assembly and stuff