Originally Posted by Humtek
The AWD system in the XI is rwd bias, meaning you mainly run in rwd and the front doesn't start gripping until the rear slips.
The BMW Xi system is actually 40/60 F/R full time for normal driving, and up to 0/100 or 100/0 when either end slips.
The whole idea of running a staggered set up is to reduce oversteer in a high power RWD car by making the rear end harder to slide sideways. In an Xi it is mostly for cosmetics since it doesn't oversteer that much to start with.