Make sure you find a diff specialist to install it - this is not for the inexperienced. Make sure they know and can set the Pinion depth, the Backlash, and the Preload.
Also, there will be additional parts required.
- Stub axle seals (may be provided by your supplier).
- A rebuild kit that includes a special single-use nut that goes on the pinion shaft.
- The bolts that hold the ring gear onto the diff (Steptronic) are stretch bolts that technically should only be used once, but you may get away with reusing them in this application.
- BMW uses a special snapring that not only holds things together, but acts as a shim to establish one of the clearances - and .002" difference in that clearance can significantly affect the life of the rear end.
All of that said, the LSD makes quite a difference.
Have Fun,
Rick