I will put in my $.02 here. I don't think you need anything other than regular car wash. I just do the wheels after I have done the rest of the car (so the wash doesn't get so dirty) and use a brush and sponge and the rest of the carwash. Your concern about the clearcoat is valid. You don't want anything to strip that off. Besides the wheels generally come clean very easily with just the car wash.
Yeah, I was my wheels every time I was the car and they just wipe off...I'll wax the rims to help keep dirt and brake dust from sticking, the problem comes when you don't wash the rims regularly...then that stuff sticks.....
however! I DO take a cleaner like simple green or similiar and from time to time spray the rubber and scrub it with a brush. The tire dressing you apply will turn the rubber brown, mostly from dirt and such getting imbedded in it and drying. tires look like brand new when done!
Meguire's used to make a TIRE cleaner...that stuff was awesome! but haven't seen it of late.