Two SUVs with some similarities, but otherwise different in most aspects such as the model year, starting price, horsepower, fuel economy, and maximum occupancy. First of all, the 2016 Porsche Cayenne is priced $34,600 lower compared to the base MSRP of the 2013 BMW X6 M, which is older by three model years. Also, the 2013 X6 M has a more powerful engine than the 2016 Cayenne, and it gets 4 fewer miles on a gallon of fuel. And finally, you'll seat one more passenger in the Cayenne than in the X6 M. Among similarities are the body structure, market segment, ground shadow size, and height.