I finally got an answer to this thanks to my local parts manager who called BMW (and I suppose spoke with the district parts manager or a deligate).
apparently the sports muffler has black tips and costs $5 more - that's it.
Fred Meloan did tell me (after checking with his parts guy) that all US cars already have the sports muffler but this didn't jive with me since the ETK showed that there were two additional parts required, a vacuum plug and a tie strap.
so now we know.
oh well, at least the OEM muffler is already a straight through design.
okay, so now I'm thinking about removing the resonator or replacing it with the supersprint straight through resonator.
So I suppose we can just disable the flap ourselves and essentially get a "sports muffler"? BTW does the flap exist for noise reduction or torque production?
This is an older thread, you may not receive a response, and could
be reviving an old thread. Please consider creating a new thread.
BimmerFest BMW Forum
A forum community dedicated to BMW owners and enthusiasts. Come join the discussion about Bimmerfest events, production numbers, programming, performance, modifications, classifieds, troubleshooting, maintenance, and more! Bringing the BMW community together.