Originally Posted by E34Mike
nice growel.. but not something thats gunna be awfull at wot.. or on long highway jaunts..
magnaflow dual in/out 2.5", if you want the deep rumble more, choose the offset ones. A more F1 flavor, straight thru.
NickP has S50 with custom system with Magnaflow, and it sounds amazing, has that muscular rumble at low rpm, and that f1 scream at high end.
I'd do the header back with x pipe, then use 2.5" resonator for each pipe, plus the muffler. Should sound amazing.