What color calipers?

ElVee

I'd go red for the poll above, but I think even normal red would be fine. Yellow would be nice, too. White is too busy and Gunmetal/black/silver too boring.

Edit: Just from a design/style standpoint, your main colors are red and black, so they'll match just fine, even if the red isn't matte. But you can also try to match the ancillary colors, which basically are silver (door, lights) or yellow (turn signal lights), and it'll still pretty much match. I just think yellow or even red are more interesting.