Powder coating is AWESOME stuff but I do want to mention another system that has a lot of merit:
Base clear coat.
The system I use is Dupont "Nason".
Selecting a finish system is a lot like buying a boat, MANY MANY compromises.
I'm not taking anything away from powder coating, I just want to mention that when powder coating is not convenient nor possible there is proven high tech chemistry in other avenues.

Neal