You have the factory silver metallic calipers like mine, and they look great as is. They REALLY match your car and look fantastic as is. BUT, it is your car, so you do what pleases you. I would make some fake covers from cardboard and paint them the colors you are thinking about and place over the actual ones to see what you think, that way you can make a decision before you do something you might regret. Photoshop might be an even better idea, except you can't see it live and in person.
stunner109, take one wheel off, cover the caliper with colored tape of your choice, put wheel back on. Now what do you like?, it will give you an idea of what you want. Your C7 masterpiece looks great the way it sits now.
No need to paint them, of course, but if you really want to, I personally recommend an orange hue. Not screaming bright reddish-orange, but more of a yellow-orange. #FF9900 something like that. Your car looks like a dark gray, so orange accents will look trendy and not take away from the aggressive look of the car the way a "cooler" color like green or blue would. That's just going on my gfx designer feels.
Adding to the orange....I saw a black GT-R with black wheels and it had orange calipers. It was definitely different and I thought it was striking. Just a little bit of pop and I've never seen orange before. It was a lighter metallic orange. Nice stingray by the way....
80% of this don't do it stuff is coming from people with red or yellow calipers, hmm. It doesn't coordinate they say? But the same grey car with red calipers coordinates with what?, a red interior, maybe when visible?
I think blue not only "coordinates" with grey, it looks dang good, green would be a stark contrast, and while not my taste, a very unique idea. I really like the idea of painting a piece of cardboard and putting it there, make a quick cover, easy test.
The key, it's purely opinion, and asserting anything past that while not offering a method to prove or test the idea is crap. I've got a white car with red calipers, does the red interior really "tie" it together, nah. I love the stock Grey color they are the stealth bombers, but the red in my case just pops, woulda liked brembo light silver, or gold, or white with red script. There are people on here spending $5k-$10k+ to replace parts with ones that do absolutely nothing better than the OE part just for looks, so I will take it all to be opinion with very little weight when it's enforced.. Rock em tyedye if you can figure out how.
I vote ZR1 blue or a slight modification of it.. Enjoy it all.