Oddly, the M4 jogged my memory a lot of the Ford Mustang Mach 1 that I recently examined, and never just because each cars have been battleship gray. Both have similar energy and poise, although the Mustang does it with an old-fashioned American V8 under the hood and the BMW with much more finesse. This isn’t so much a dig on the M4 as recognition of the truth that it has been one of Ford’s efficiency targets for the Mustang lately. BMW’s newest slogan is Sheer Driving Pleasure, and…