Red is faster.
Sorry to be silly ... No I'm not. Anyway ...
I had to decide what color to paint my aged Raleigh and I couldn't make up my mind so I went with clearcoat over bare metal. So yeah, it is a tough decision.
Black on red looks completely different than silver on red. To me, black on red seems more sinister, more menacing, while silver on red seems almost ethereal, almost celestial. Most younger more competitive people would probably rather look more like Rambo or Terminator .... not that most people even notice that much outside of their own stuff anyway ...
Red and silver probably won't look as mean and bad-ass ... but some folks really don't care to look "mean and bad-ass."
Maybe google images of red bikes and find a few in red with black and a few with red and silver and see what you think?