To add a few things:
1. I changed my MTF at 68k and replaced with BMW OEM (still under CPO). I got the old fluid analyzed by Blackstone Labs, and looked pretty good.
2. The same shop (who I trust) sold me the XO diff fluid for my car. Like another person mentioned, I think the XJ is for limited-slip diffs. My E92 has an open diff, can't speak for Euro-spec cars.