2016 BMW 6 Series Coupe is the newer version with some differences, such as the model year and fuel economy.. First of all, the 2016 6 Series Coupe is more fuel efficient; it gets 1.1 more mpg than the 2014 6 Series Coupe. Among similarities are the body structure, market segment, starting price, horsepower, ground shadow size, height, and maximum occupancy.