I am not sure the extent... But, where the sheet metal meets the frame on the rear door there is corrosion. The seal is destroyed and now starting to come apart. You cannot see through it, but I can basically rip off the seal where it is beaded to the frame.

I will try and get a couple photos today or tomorrow. There is corrosion on the seal, and bubbling is occurring from there to the corner of the door (making it's way to become visible to the outside when the door is closed).

__________________
BMWCCA