Evo gives the X6M a good test drive. They basically hate it.
Link:
http://www.evo.co.uk/carreviews/evoc...4/bmw_x6m.html
2.5 starts out of 5.
"X6M fails to impress like an M-car should on track, feeling unsettled under braking and struggling with understeer."
"...much the same could be said for the £20K cheaper xDrive50i, which isn't that much slower and sounds like a proper V8. If you want a quick X6, that remains our recommendation. The X6M may be fast, but it's an even worse idea than we feared."