I used legend 5 brake caliper lacquer. I know someone who used spray engine enamel and IMO it doesn't look as good as lacquer. The finish just doesn't look as thick or rich. Here's a pic (the rear f'ed a little because of the panorama).

The kit costs ~$25 and is enough for all four calipers. Either way, prep is the most important. The more time you spend the better it will look in the end.

-Louis
1998 Black E0 #3826, lightly modded