What you need is called ceramic coating. Its applied the same way as powder coat but holds up to much higher temps and helps keep underhood temps down. It also helps with performance by keeping the exhaust temps higher inside the header which allows for better flow, (can't remember the exact technical reason why this helps right now though). Make sure the part is media blasted so there is no rust on it before it gets coated and make sure that the inside of the pipes are coated as well, ask before you get them done, it works much better when both side are coated.