I had the same question when M-performance parts just came out... Tried photoshoping (i.e. changing color on white car with m-performance parts to black color), but due to numerous highlights, reflections, etc. it's a bit like cutting blocks with a razor - just doesn't feel right.
My google research came to only one decent example of how M-performance/CF parts look on a black bimmer -
here's the link to M550d. Still not completely convinced, but already asked the dealer to give me quotation for the parts and installation