I would not worry. I know of some guys that have PC their rims and used them when they tracked their car with no problems. De3pending on where you live the roads will do much more damage to the rims than powder coading them.

 

I have powdercoated 2 complete sets of AP1 wheels as well as another set on my '90 CRX-SiR. I have zero concerns about the powdercoating process.

There are however a few things to be aware of - powdercoating is thick and the way the OEM wheel fits up to the oputer hub/rotor is very precise, after the wheels are powdercoted you may need to sand the innder face of the wheel where is fits over the outer part of the hub. I have found the powdercoating has added just enough thickness that the wheel did not just set on perfectly, so I did the sanding, no big deal. The other issue, also no big deal, is to sand the inner face slightly where the lug nut comes in contact withthe wheel, by roughing up the surface the lug nuts will have less of a tendency to loosen slightly, but this is mainly a track use sort of thing.

My track rain tires, dark metal flake grey


My street tires, black and silver

 

Nice, I've been thinking about powder coating mine either flat or gloss black.

 

this was my old car with gloss black powdercoated rims