Seems to me like ceramic coating would just insulate the headers, keeping them from dissipating the heat, which would then lead to higher head temperatures. But I could be wrong.
The whole point is to keep the heat/exhaust IN the pipe, for as long as possibile.
Ceramic coating is the same idea as wrapping your pipes with headerwrap. The more heat kept
in the pipes - the more power you will make.
Jett-hot offers a longer warranty, but their turn-around is MUCH slower than a
company such as Lo-Ko. Jett-Hot is a HUGE company, and I have heard more times than not, peoples headers getting "lost" in the shuffle.
I have dealt with Lo-Ko for years, and
NEVER had an issue with their work...