I'm on the fence with the 2 colours... which is why i resorted to this lol

I'll try to photoshop but im not too great with that... haha

 

rough photoshop pictures...

Blue Calipers

Red Calipers

 

Personally, I'd leave them as stock. Painting calipers makes them stand out. So, in effect, you'd be showing off single pot calipers that have the pot behind the rotor. Which, personally, I don't really want to draw too much attention to. However, it is your car, and I always believe that people should do what they like to their cars. Between the two colors, I'd go with Red.