i was told by the ceramic coating guy that black or silver was going to be my best bet. the other 'colors' tend to fade and discolor.
and honestly, if i'm going to wrap the exhaust...who cares what color it is? black might be the way to go.
I have done silver and black a couple times on my own junk. I would just do it in black and wrap it. Or give them a brushed look and clear ceramic them...