Not sure if the stainless would get hotter than the surrouding aluminum, but it will retain the heat a little longer. Check that. Senior moments suck.
It could be the aluminum retains heat longer. Anyway.....the retention of heat by 4 studs is probably going to be insignificant anyway, as I doubt it'd be much different from a stock engine.
Given that these engines run at low compression, I don't see any problems switching to stainless. With regular maintenance, problems with the studs, etc. should be non-existent.
Now...to find all the stainless studs, etc. in metric sizes and in the right lengths.