I think Silverstone is a beautiful color. Very striking, classy and unique to M cars. I think it looks best with Silver or black interior.
I think it looks the worst with fox red. Silverstone has a blue hue to it, and fox red has an orange hue to it. The blue and orange just don't look good.
The standard (non individual) color I dislike the most is Jerez black. I don't care for the blue hue in the black.
Audi S6 * Audi S3 * Porsche Cayman GTS
--Former BMW M3 owner