Intermitant buzzing sounds like it's coming from the door locking pin. Upon inspection the dealer applied felt tape to the edges of the inner and outer door panel. Still not fixed. Now there are some new buzzing noises coming from the passenger door. I'm going to ask them to drive it for a day and deal with whatever they hear eminating from any part of the car. Maybe the issue will only be resolved when my lease expires next year and I get a '12 model.

 

I have that same buzzing going on in my '10 MCS - sounds like it's coming right from the locking pin. Sometime I lock the door just to shut it up. Please let us know how it goes...

 

Yes, my locking pin will buzz as well. Only solution I've found thus far is to lock the doors.