I would rec'd reading all the threads on the E83 board, and peruse the E53 board, as the X5s in your MY range are very similar, engine/trans/gizmos/stuff, et al, to your car.
E83 is thinly posted...you might set your Thread Tools to always show Today's Posts or New Posts, rather than just wandering back to read the E83 board. Lots of good stuff that may relate in other forums.
X3 (E83) Forum - Xoutpost.com
X5 (E53) Forum - Xoutpost.com
You might also post current mileage, what docs/records you have eg service history, the 'model', and maybe some pics.
Welcome to the Boards...
GL, mD