Anybody know exactly how to do it? Do I need primer and clearcoat, or do I just spray the paint on and thats it?

Really up to you, I would give them a good wipe with some rubbing alcohol, one coat of primer two of colour colour and then two or three of clear.

If you get any drips or runs just sand it back.

Need to wipe them with wax and Frease remover or Prepsol. Then 1 or 2 light coats of plastic primer. This makes the paint stick to the sensor. 2 coats of colour then 2 or 3 coats of clear. Its that easy. Just take your time

at work we give them a light sand with wet'n'dry, clean en with prepsol and then giv em a light coat of paint.... go too thick on the paint and you'll get false triggers

Thanks Guys! :)