UPDATE: they replaced the vapor barriers on all 4 doors. They said BMW USA only reimbursed them for the rear... they did the front out of their own pocket because BMW USA would not cover the front... not sure why?? They made sure to tell me over 4 times that they did the front out of their own pocket..... that is great if it solves the problem. However, the problem is still there!!!!! Now, the car has over 50K miles (out of warranty) It is still CPO'ed. I have had the car into the dealer several times when it was under the 50K miles, now they are freaking telling me that I have to pay for a min. 1 hour labor for them to diagnose/look at the problem if I want them to fix it. I said, "I had it already in 3 times when the car was under warranty and you could not fix the problem, now I have to pay for you to look at it because you did not fix it properly the other 3 times." He said, "Yes, if you want us to look at you must pay for us to check it out." That is F&*king BS!!!!!!

I think it might be the sunroof seal because it is load inside the car when the cover is open.

 

Touch the carpet behind the front seats. If the floor is wet you have the same problem that I had with my M6. I had a leak in the door seal that allowed water to seap past. After a wile the moisture in the air inside the car began to seperate the leather from my dash. The replacement dash cost six grand!!! I had warranty!!!