Has anyone used Jet-Hot coating on their headers or on their cat-back exhaust. With engine compartment heat being such a negative, the 50% reduction in heat radiation from the exhaust system would seem desirable. Is there a problem with all of the retained internal header heat voiding the aftermarket header manufacturers warranty on the cat? There is also the benefit of a slight increase in horsepower due to the inproved flow velocity due to the internal temp increase. Any experience with or thoughts about this? Joe