[DanEC]

I have to admit to some skepticism also. My headers, primary pipes and mufflers on my under car system are all ceramic coated in black inside and out. My mufflers are Spinteck baffled mufflers (no packing). Now how effective they can actually coat the inside of pipes and mufflers I don't know - maybe not too well.

I think part of the problem may be the use of IR guns to shoot surface temps on the headers & pipes. I read a paper once that IR guns are mostly calibrated to a flat black surface and shiny or silver color can introduce error into their readings. Since most people use a silver, somewhat shiny coating - well relying on temperature reading on them can be a problem. My mufflers are under the seat area and I've shot temps on them of around 550 degrees - not excessively hot for exhaust gases but certainly not as low as I would expect from all the claims for outside heat refraction on outside/inside coated mufflers. Since they are flat black I tend to think theses readings might be more accurate than if I had a silver coating. Pretty much same at the headers although I don't recall specific readings.

So, I'm not saying BS on the claims. But I am a little suspicious of their validity.