Ahhh, I feel your pain!! I was messing around trying to get at it all the other week to inspect, looks to be a friggin nightmare! I was pondering whether you could cut the air filter housing part of rocker cover off, to help with access.. but that might be making a big mistake! :p also, looked like you’ll need thin wall sockets/spanners to get at turbo bolts, I tried a normal spanner and it was too thick.. I guess if you can get exhaust out of the way, remove turbo bolts through the top, should be able to get at the manifold bolts, and slide out underneath. (Potentially leaving turbo more or less in place)

Good luck, have fun! And be sure to take lots of pics and do a write up on it please!

__________________
2004 X5 3.0d
2010 X5 40d

New Zealand