M Performance exhaust

[ClausCoupe]

I did an install last week, but I am not happy at all.
There is a resonant, low frequency rumble when revs are low. It's actually frequencies that you feel in the driver seat when you are on low revs (1500-1800).

I had the dealer mount the square M exhaust tips (like on the 650i) instead of the round M Performance tips, but that shouldn't have anything to do with this.

It's pretty uncomfortable, and irritating.

Has anyone got a clue, or experiences? I think it's strange that BMW produces an exhaust system that really is "too much" and with bad resonance sounds that plants itself in the chassis of the car.

Any others out there who has installed this exhaust system?

Best

/c

[BillCB]

Sounds like there may be a mechanical "link" somewhere - one part rubbing another. I've had this when I've installed a new muffler and hung it badly (not on a BMW!) so it vibrated against a body part.