Now that the 6 series convertible and coupe are no more, the new flagship for BMW is the 8 series. We can argue that these are really new 6 series cars, but thats not my call.
The M version is where all of the fun comes into play, and these are beastly cars with a lot of innovations, technology and horsepower jammed into a single platform.
The heart of the beast is a high-revving 4.4-liter, TwinPower Turbo, V-8 engine that produces 617 horsepower and 553 pound-feet of torque (the Competition has a 17 horsepower upgrade over the M8). 0-60 mph sprint for the M8 Convertible Competition is 3.1 seconds. The official quoted numbers tend to understate horsepower; the M5 Competition dynos closer to 660 horsepower than 617, (my 2014‘s official number is 560hp but it runs closer to 600hp).
Other M8 changes over the M6 include an automatic only all-wheel-drive system, with 3 distinct working modes called 4WD, 4WD Sport, and 2WD — 50/50, rear biased, or all rear drive. (The rear 2WD option is designed for the track).