G2 Caliper paint Kit. Available on Amazon in many colors. This is the best I've found. It's an epoxy paint and holds up well. I used their kits on a Corvette and my R56 with excellent results. Not cheap, but well worth it IMO. You really need to have the car on jack stands or a lift to do it properly.
No problem. Best technique is to remove all 4 wheels and blow the dust off your calipers with a compressor. Then go around the car and clean each of the calipers with the included brake cleaner and a stiff brush. I would recommend safety glasses for these steps. Once you mix the two part paint you have a couple of hours to work with it. I would recommend a better quality brush than the one that comes with the kit too. Start with a single coat on the first caliper, don't get carried away and lay it on too thick, and then move on to the next. By the time you get back to the first wheel the paint will be dry enough for the next coat. Don't worry about brush strokes showing because they will disappear overnight. Just keep circling the car and adding coats until you have the look you want. On my R56 IIRC it was 5 coats. I believe they recommend waiting 24 hours before replacing the wheels.
G2 Caliper paint Kit. This is the best paint I've found. It holds up well. I used this paint on my F55 with excellent results. You really need to have the car on jack stands or a lift to do it properly and dont drive it for a few hours until it is dry.
Just painted mine with G2 caliper paint. Temp outside her in New Jersey was like 40F. I have a propane garage heater but only used it while painting. Easiest way to do it was to get the car up on jackstands, remove wheels, remove brake pads and reinstall calipers (so you don't get any paint on them and can paint easier). Left it over night in the cold. Was fine to touch so reassembled everything and just drove. No running, no discoloration, looks amazing.