Admittedly, the X6 M seems like odd selection here for comparison since it is a massive and 5200 lbs SUV being compared to sport wagons.

1st Place: Porsche Panamera Turbo
Have you ever wondered what Zeus would drive? Stop wondering. Start lusting after the world's best four-door supercar.
2nd Place: Cadillac CTS-V Sport Wagon
This is a supercharged, 556-horse-power, 551 pound-feet of torque, rear-drive station wagon-with a manual. Prayers do get answered.
3rd Place: BMW X6 M
Earns its M badge in every aspect save one: desirability. More a historical footnote than anything else.
http://www.motortrend.com/roadtests/sedans/1106_2011_bmw_x6_m_cadillac_cts_v_porsche_panamera_turbo/index.html
But hey, they're obviously masters of the spin.