I put the Performance Exhaust on the wife's 128i right after we picked it up at the dealer, and we both love it! Doesn't drone on the highway, and is mellow until you step on it, after which it really growls! What's not to like? Bigger "finisher" pipes look great, too.
2013 F30 335i M-Sport 8AT/MPE/MPPK, 2011 128i M-sport Cabrio 6MT/PE