The M5 wheels will not fit as the offsets are too low. Regarding xi wheels in general, BMW's upgraded sport 124 wheel is available in an xi-specific fitment with higher offsets. Check realoem.com for part #s; they differ from the rwd 124 wheel. While the xi's are awd, they are rwd-biased and there is no problem running a staggered setup. BMW's own upgraded tire/wheel package for the xi is staggered.
M5 (F10) | Alpine White | Black Merino | Fineline Anthracite
640i GC (F06) | M Sport | Sapphire Black | Amaro Brown Merino | Red Sycamore | M Performance Exhaust
535xi (E60) | M Sport | Platinum Gray | Black Dakota | Walnut | Dinan S2 | BMS DCI | KWv3 | Beyern Mesh
525i (E60) | Sapphire Black | Black Dakota | Walnut