Two Sedans with some similarities, but otherwise different in most aspects such as the starting price, horsepower, fuel economy, ground shadow size, and height. First of all, there is a notable difference in the starting price of the 2016 BMW M6 Gran Coupe, which is $186,500 less than the base MSRP of the 2015 Bentley Mulsanne. Also, a bigger engine usually means less mpg. But the 2016 M6 Gran Coupe has a more powerful engine and it gets 3 more mpg than the 2015 Mulsanne. And finally, not only Mulsanne is slightly larger, but it's also taller than the M6 Gran Coupe. Among similarities are the body structure, market segment, and maximum occupancy.