Are you honestly trolling the X5 forum....?
If you have not figured out the weak point of the X5 diveline, it happens to be the transfercase. Additionally if you can not figure out that dumping tons of torque through the X5 doing donuts may not be the safest thing to do in this car I can't help you. Having blown two transfer cases in an e30 ix doing the same shit, a differential in a Euro /M3 by dumping the clutch at 3k rpm to launch, I may be some what overly cautious. But again trolls to the X5 forum, what next?