I think the switch to aluminum may be better for temperature too. I am no metal expert, but I think stainless may dissipate heat slower than aluminum making aluminum a good choice.

 

For very little cost the part could be sent to someone like Swain for a heat dispersant coating. Any metal will act like a heat sink. The coating would solve the problem.

 

Plastic heat soaks also, but it does take less time to cool.

CJV: you might know this, what was the salt water(?) blasting/polishing that was once tired on turbo impellers? I seem to recall a process that put an coating or polishing to the wheels for better air flow. I don't recall if it was only experimental or actually has a use.