I also have an update for you guys in regards to the belt squeak saga.
Monday morning I started the car and was greeted by this:
Would only happen after sitting for at least an hour. So similiar to the squeak, which after being left to sit, it would squeak once and not appear until another cold(ish) start. Mine gotten to the point it would squeak always in warm weather from 1-2 and to 2-3, sometimes even 3-4 upshift.
As I was scheduled to get my xDrive transfer case replaced, I showed them this. Today they called me that they are going to replace the belt tensioner.
I will post an update to this in the summer if the squeak comes back, but as someone else also mentioned that after replacing I believe an alternator (I was told the tensioner is next to the alternator) his squeak was gone. I would advise anyone with the squeak to get it resolved. It will eventually bite you in the back.