BMW just recently rolled out its new flagship 7 Series sedan. It didn't take long for it to introduce not one, but two performance versions as well. But what we've seen until now could only be the start as the Bavarian automaker looks to close the gap between the 7 and the Rolls-Royce Ghost.

An M7 would have to pack some serious punch, considering what's already on offer. Both the Alpina B7 (4.4-liter V8) and M760Li (6.6-liter V12) each offer 600 twin-turbocharged horsepower and 590 pound-feet of torque driving to all four wheels, capable of hitting 60 mph in the threes. The full M version, then, might need a good 650 hp or more, which would put it out in front of everything else – including the Audi S8 Plus (605 hp) and Mercedes-AMG S65 (621 hp).