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.