different uses.. this is ceramic like header paint.
a non coated header vs a ceramic coated header can have a big engine bay temperature difference.
the principle is the same for intakes to keep a CAI from absorbing the heat of the engine compartment on the way in.
and from air cooled vw people (4 wheel drum brakes) use it to keep the drums cooler..
i have not seen "dyno" type testing. but i have seen laser thermometers pointed at the drums to show differences in temp.
of course real race people drill a bunch of holes in the drums for cooling too..