powder coating and ceramic couating are two different things. Jet coating is ceramic coating and will definitely be able to withstand the temperatures!
You can even get it in different colors. I'll go with silver.
I found them on the web, same process as Jet-Hot, but less expensive. I had a header coated at Jet-Hot a few years ago, still looks great. May be selling it, (square port 6 to 1 Z header). Silly me has a square port head, did'nt fit too well... seems the flange on the header is kinda small for the stock gasket.
All the above posts about powdercoating not sticking to headers is true. I inquired a local powdercoating shop about coating a header... was told that powdercoating will only stick to surfaces that does not get hotter than 400 deg F. If your parts gets hotter than 400, gotta use ceramic coatings!