What we have here are two SUVs from BMW with some differences, such as the model year, horsepower, fuel economy, height, and maximum occupancy. First of all, there is a difference in model years. The is 2 years newer. Also, although the 2016 X5 M has a more powerful engine than the 2014 X6 M, it gets 1 more mpg. In addition, the X5 M is slightly taller than the X6 M. And finally, you'll seat one more passenger in the BMW X5 M than in the BMW X6 M. Among similarities are the body structure, market segment, starting price, and ground shadow size.