I've been pulled over several times since getting my CCW, and it's always been met with in a positive light. Take every precaution, car off, interior lights on, hands high on the wheel, and most of all be respectful and courteous. They deal with a lot of shitty people who hate them for some reason. Just being a decent human being and doing everything you can to make him/her at ease is appreciated.
Hell, a couple times I've been told they appreciate me carrying and wish more people did.