HARTGE Exhaust for 135i. Heard this the other day. I think I like the way this exhaust sounds... a lot! Louder but without the fart quality found in some aftermarket exhausts. The price on HARTGE stuff is pretty high. I imagine $4k at least. But I do like the more 'high tech sounding' tone of this system. Plus you do get proven performance gains as well.
http://www.youtube.com/watch?feature...&v=_zATz5Q4Vzo