I know of someone painting tue grilles on a 2012 650. Most places don't recommend it because the paint won't stick well to the chrome but he hasn't reported any chipping or peeling. I can't see a problem if you scuff and sand the crap out of it.
If you like the matte black look, then Plasti dip is always an option. That stuff sticks to anything and it doesn't look bad at all if applied correctly.
Last edited by Itinj6; 10-14-2012 at 06:58 AM.