Whats the difference between nickle plated headers vs ceramic coated headers? What makes ceramic coated more expen$ive?
And out of curiosity what is EGR and what's it for?

 

EGR = exhaust gas recirculation, it takes some exhaust fumes and puts them back into the intake manifold to reduce the risk of detonation and keep temps lower. Coating makes the headers look better, last longer and keep heat in.