Re: Powder coating
If you don't get them ceramic coated, then, they will never be ceramic coated. There is no coating from the factory...not being coated isn't going to hurt anything. Coating is just a way to improve things, not prevent issues.
Powder may not hold up to the temps that headers will see. The exhaust gases are extremely hot and can push surface temps to temps much higher than the curing temps for powder coats. This could crack or cause the powder coating to melt off of the headers.
"When I know more, I'll be forthcoming. Or I won't be forthcoming, and I'll be honestly deceptive." - Les Miles