I had my OEM calipers powdercoated gloss black on my previous car, looked clean (car was blue).
I'd say for a silver car you really can't go wrong with whatever you choose. I think the quality and cleanliness of the paint or powder job trumps the color itself. Even if you went with black or red (my two choices), if the job looks sh*tty they're gonna look like crap.
i voted for silver. on almost any color, i think silver looks good. black is a close second for me. clean and simple is the way to go! i think red is just too flashy. love the car btw! cant beat a silver new edge!