I have no problem being smoked by an M5 Wagon, but it should look mean as hell when it's pulling up behind me. Just looks like a wagon. Remember when the E30 M3 look completely different that a E30 325e? Now you can't tell M cars unless you see twin exhaust pipes or badging. With the way BMW is designing cars now, the headlights will be reaching right up to the side mirrors.
But yeah, I'd take one.