Before I would buy into any of this (this runs hotter/cooler than that) I would
like to see some kind of quantitative study, i.e. a quantity of different size
engines from the same manufacturer and then different manufacturers. Other
things also like what seasonal additives the mogas may or may not have. After
13 years of dynomometer testing on air cooled VW engines I have seen the same
motors react ever so slightly to things like different fuel, etc. due to things
like, for example, timing (ignition, valve, whatever) being a tick different.
What I'm saying is that one engine may seem to run hotter with a different fuel
while another may seem to run cooler with the same switch.

Jim