With 500 horsepower and 383 lb.-ft. of torque, the only question to ask about performance is: How much can you use at any given time? Acceleration is rapid to blindingly fast. Zero to 60 mph is achieved in less than five seconds. The 5.0-liter V-10 pulls strong from just off idle all the way to redline. BMW is coy about this engine’s relationship to the V-10 it used to build for Formula 1 race cars. But with stepless variable valve timing, a special lubrication system and 10 individually controlled throttles, “inspired” sells it short.