Even though I do agree that the headlights are odd (thats the worst I'll say...
), just think about this scenario...
...You're a chasing a guy in your beast at 1am without him knowing it. Prolly some 89 5.0 Mustang or something that has been pressing you all day to race. you slowly come up on him (on the highway), cruising at 60mph. He notices in his mirror... what seems to be... eyes! Of course he can't really see your car because a general amount of Americans have less than 20/20 vision, and it doesn't help you have a Jet Black M5. As you are about 4 car lenghts back... you flash your xenon's on him... which sends a little tingle down his spine because he knows the guy behind him is serious. As he starts to accelerate... the M5 does too. When you really get going... the available torgue in the M5 does it's job and all the 5.0 driver see's is your tail lights. little does he know he was passed by one the most technologically advanced supercars in the world.
...well... you can do that in any M5 really... it's the emotion that counts

.
The lights ALSO make the M5 look more pronounced also (just like the black stripping)... which detracts away from the stealth. It's not everyday any old car has headlights looking like that you know...
Cheers,
Matt