ok well a guy on base has a brother that does professional ceramic coating...so i gave him my headers and he said hes going to put on a 4 mil thick coat for 100 bucks..ive seen his work and they look great! my questions is this...is ceramic coating cosmetic only? or does it help with heat?

 

Keeps heat in the primaries, increasing tube velocity, increasing scavenging, which increases HP. The heat stays in the primaries, and does heat up the engine compartment as much, reducing burnt wires, melted components. Reduces tube metal temperature, reducing thermal stress cracking of welds, and oxidation (rust) of surfaces. Extends header life.

Both the inside and outside of the tubes need to be coated for it to be effective.