Day 7 of owning an M5, I installed the M Performance LCI Grilles. GetBMWParts was the lowest place I could find them, shipped for $302 total.
Installation was simple, DIY by
LACSTER :
http://f10.5post.com/forums/showthread.php?t=422572
Product: http://www.getbmwparts.com/partlocat...catalogid=4462
The transformation of the front with the grilles alone is amazing.