I've shot wheels with good results before using both PPG (Catalyzed DP50) and Endura EP-Hi primers. For the primers a standard syphon gun is fine, the EP-Hi is a high build epoxy (couldn't tell that from the name, huh?) that's better if you're looking to fill and sand, the DP50 is great to shoot and top coat. On Aluminum rims a pre-treatment/cleaner like Alodine will prevent chipping off better.
For the top coat, Endura single stage catalyzed urethane is some serious tuff stuff. It's also some serious noxious stuff so invest in a good respirator and don't get it on your skin - wear coveralls and gloves. It performs very well on wheels, inner fender wells, floor pans etc, and shoots very well from one of those little HVLP door jamb guns with the fine tip, like the ones at Harbour freight or KMS. It does not clear coat well (not designed to) but on wheels and inners it looks good enough to not matter.