i'd paint them black. it looks harder with the black rims. i painted the centres of my 001's a dark gunmetal grey and was soooo pleased when i bolted them up together.
I was thinking about painting my ones gold in the middle and buying some gold plated bolts would that look good or not? but to the question going around i reckon black looks good but i like the bling factor 
no no no gold on a red car is a no no, the gold paint won't match the gold plate bolts either........