Kalun D,
First, let me say your GT looks fantastic. Kudos on a well built car.
I have to reply vis-a-vis your discussion about the "science" of the different metals. I think you're mixing up conduction and convection. Whether your headers are stainless or mild-steel, they will both get hot from the exhaust gases flowing through them. The "heat they give off" is the heat you feel from "convection". If you have stainless headers at 1000 Deg F and mild-steel headers at 1000 Deg F, and you hold your hand 1 ft away from each - guess what - you feel the heat from both as the same since it's the convective properties of the heat through the air. The differences in the metals are significant from the standpoint of corrosion, strength, etc. Now as for coatings - this brings up a different set of issues - is the coating reflecting any heat energy back? does it have any insulating properties? etc?
Anyway, just my two cents. Again - great looking GT.
Mitch