With its polarizing oddball looks, premium price tag and questionable need to exist, BMW's new "Sports Activity Coupe" (their PR speak, not ours) isn't for everybody. But with a choice of twin-turbo engines-- a 306 hp 3.0-liter I-6 from the 335i or an all new 407 hp 4.4-liter V8-- more electronic aids than Stephen Hawking and bigger rubber than a Z06 (315/20s at all four corners), the X6 is going to make some customers very, very happy. Here's the skinny on the Bavarian fat: both the Infiniti FX50 and the Porsche Cayenne Turbo have something to worry about. Despite the X6's bulk (more than 5k lbs of it), this X5-spin off can dance the dance. Grip is endless and there ain't no body roll either.