To be fair, painting the bowties takes a lot less time.
I am in agreement with the post up above - I typically like them to match body color...but when you have a darker color body, then that doesn't quite have the same effect. Black always looks good, though it just means they hide even more behind a black/gray wheel, but being a stock caliper, that might not be the worst thing. Those who notice will appreciate the painted caliper, but those same people might wonder why you painted them a bright color if they're just normal stock calipers.
That said, if you did do a contrasting color, it usually works well to coordinate it with something else on the exterior of your vehicle - or a color you might plan to add to the exterior.
If I were in your position, I'd probably go with a black caliper, behind a gunmetal/gunmetal wheel given the color of your car.
