Actually gold is the fastest colour. Then silver, then anything else in the light sepctrum in the order of the rainbow, and lastly black. Why?
well, liek when you wear black on a sunny day you roast right? Cos it absorbs the heat. Therefore a black car will absorb the weight of the sun, and the sun being the largest object in the galaxy weighs a fair bit, so black cars carry all that weight and therefore are slow. gold is the best heat refelctor (as used in Mclaren F1 engine bay) so it repels the light, and in fact is so good at repelling, it even gives off its own heat and reduces its own weight, thereby making it even faster than physics would allow.

On this line of thin logic therefore, maybe Xray colour would be even faster.

Now to chuck a spanner in the works - how fast would a "black light" one be?
