"New Cerakote ceramic-coating lowers the heat radiation on all exhaust components by more than 30% to reduce component fatigue and extend your truckmount life—plus keep the van interior cooler!" Big difference. So where does the dirt......I mean heat........Where does the heat go? It's only holding radiant heat in from the surface. That additional heat is has to go somewhere. Seems it's either out the exhaust, into the water, or back towards the engine manifold. What about when there is no water moving? Will the exhaust alone dissipate the additional heat with no flow? If not, it's right back towards the engine and beyond. Manifold and engine temps will tell the tale.