Stainless Steel Headers

[Samtech]

Stainless has a lower melting point but is less thermoly conductive, it will heat up slower. For this application it's moot... The thickness of the header will have more effect on the time in which it heats up or cools off.
But I agree with the above, bends near the heads tend to get hotter faster.
Coat them and they hold the heat in much better, last longer too.