I have seen Matte Black Grill on the M3, and I would suggest them if you want them black.
Also, I had seen black grill's for the E70 online, but don't remember the site. If I remember, I will let you know. If you want Carbon Fiber, they are about $1200.

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2011 ///X5 M (On Order)

2009 X5 4.8 M Sport Space Gray/Black Fully Loaded

2007 GMC Yukon XL Denali Loaded and Customised