Of course mine wasn't glowing like the whole system in that picture, but the manifold would indeed be glowing a hot reddish orange after I had been on sustained boost --- I lived like 3 minutes off the highway exit so it was the case that I had been blasting down the freeway at max and had generated some serious heat. After such a drive I would often make a habit of popping the hood for a quick inspect while the car idled before shutdown because I was paranoid about coking the turbo.
I don't have any hard data or anything but I can say that I noticed a considerable difference in radiant heat after the Jet-Hot coating.
I ran it like that for nearly a decade and it lasted very well with only some minor flaking in a couple of spots.
Took it off only because I switched to headers.