I used plasti-dip on my landcruiser. It's fun and risk-free. However the black fades in the sun, and it will peel.
It was a nice way to preview various parts of the truck in black without committing to it, since it comes off with a pressure washer.
EDIT: I won't be using plasti-dip on the M5. It would feel too much like shopping for exhaust tips at AutoZone.