Hey im just telling you what the ASE book teaches us
Maintains optimum engine operating temperature for best emissions and economy.
in a generally speaking, under the conditions I described above that could be a true statement.
but in a modern EFI car there is no need to preheat the incomming air charge if the atomized fuel is injected into the cylinder.
a 10 degree drop in manifold air charge temp is worth 2%HP
dropping the air intake charge 20-30 degree's is a 16-20HP kick in the butt, feel free to "run your motor hot, and give up HP"
and before anyone says "cold engines wear out faster".
I ran grandmas car for over 300K on a 160 degree thermostat.