Get the Eastwood high-temp coating. They have black, gray, stainless steel and silver finishes. I used the factory gray version. It will last forever if you prep the headers properly. A pint will last you most of a lifetime. Just mix up a little and spray it on with the PreVal disposable aerosol sprayers you can get at NAPA.

I put it on my old 230/8 and the exhaust still looks good after 20 years.. Probably could use a re-coat by now, but I am getting lazy...

230/8