If you recall, a couple of months ago, BMW has released their Performance Parts Catalog. Since then, we have already seen a few BMW 135i that have been modded and improved by using parts from the catalog.
Yesterday, while browsing on Youtube, I came across this video. From what it seems like, the owner of this beautiful BMW 135i Alpine White has replaced his/hers exhaust with one from the Performance Catalog.
Sit throught the whole video and listen to that beautiful sound, it almost makes me regret not waiting for the 1-Series :)