Well, it wouldn't be a typical production variation would it?

The plus side is, here in the states at least, there have been plenty of M cars that were Silverstone II with Silverstone interior. It is very similar, with a little bit of difference, to the colour combo you are proposing. I have been very impressed with the appearance of these cars. However, be ready to clean, clean and clean that interior. I drove a Silverstone interior M6 at the BMW driving school (for about 2 hours) and there were jean stains on the seats...Be it minor, but to someone who cares about their vehicle, noticeable nonetheless.

As far as resale, I can't help you there. Your market for vehicles differs significantly from ours.