How would I know? I am just telling you what they said!
But seems reasonable. In a related note there is a company called EVANs that makes a different coolant that can run hotter before it boils.
Coolants Engine Cooling Systems
So this would allow you to run the engine hotter without fear of boilover. I don't know what the next thermal limit is in the engine.
I vaguely remember that HONDA F1 cars were running straight water at 50 psi or so to get really high coolant temps that would allow for smaller less draggy radiators.
So I suppose the ultimate setup would be some kind of electric pump, small radiator and high temp coolant. To allow for smallest possible inlet.