I couldn't find the B Pillar Trim part listed on Real OEM so I had to pull it off my car to look. The paint appears to be some kind of rubberized coating that is starting to fail.

For anyone else looking for this information:

51.43-1 977 755
51 431 977 755
51431977755

This is for the driver's side. In my experience the passenger part number will be one digit +/-.

IMG_8866.JPG

IMG_8865.JPG

https://www.realoem.com/bmw/enUS/sho...diagId=51_2039