Spied: BMW X6 M

I really don't see any advantage to get this over a 3 or 5 series wagon (assuming bmw would just sell them here). Also, it seems like everybody praises bmw for making small and efficient engines, but I really don't get it, especially when the M3's v8 gets the same mileage as a more powerful GT500 Mustang (14/20) and worse than a comparably peak powered Camaro SS. And their engines themselves are no lighter than an LS3 or whatnot.