Any BMW model bearing the tell-tale "M" badge is sure to pack a punch. The carmaker has now upgraded the cross-over models X5 and X6, making them the first "M" editions to feature four-wheel drive.drive it! puts the new X6 M through its paces and tested both its all-rounder credentials and its qualities on the race track. It comes with an all-new 4395 cc high-performance V8 engine that delivers 555 hp and propels the X6 M from zero to 100 kph in 4.7 seconds.