I miss the character of the exhaust sound my JCW MINI had. I went from stock on my 335i to Borla which sounds pretty good above 3000 rpm, but not very good below that with a lot of drone between 1700-2300. I've got a PW Performance Exhaust coming which sounded really good on the car I heard with it on. I hope I enjoy it as much over the long haul. I wish BMW could get the same sound engineers who tuned the factory R56 JCW exhaust to do one for the 335. I know it was a 4 cylinder vs a 6 but it seems like it should be possible to get a little more character to an N54 without getting rid of all the cats and while keeping it drone free and civilized when you're just cruising.
Here's a clip of the stock JCW for anyone interested.
http://www.youtube.com/watch?v=4vwaOiGfN98