Thermal coatings, gains with alky?

Anybody have info on the value of coating piston tops, intake valves, or any other part that will provide a good return on investment? The biggest part of this question is how much gain there is with alky. With its' cooling properties, might not be much?

Look at it the reverse way, it might keep more heat in the chamber, doing work rather then heating the piston, etc, would it be as much benefit as with gas, likely no. I believe in coatings.