your going to want to take them off and paint them if you do it yourself. and after you have them painted it wouldn't hurt to have them balanced just like having them powder coated but i know if i was doing it i would just find a friend who has and extra car i could use while getting them done so i could get them powder coated but that's just my $.02
If your that concerned with the over spray (there will be very little) you can get masking tape and news papers