Scoobysport makes high quality stuff, no doubt about it.
This thread has some back and forth about the coating issue:
http://www.i-club.com/forums/showthread.php?t=99281
The debate starts at the end of page 1.
Here is another post I made on nasioc some time ago with a quote (talking about heat wrap, but the idea is similar):
Man, I know I'll get flamed for this, but it is the truth and it comes from a book on turbochargers that is published by HPBooks.
George Spears suggests: "In regard to the subject of wrapping the exhaust-to-turbine pipe, we experiemented on the V6 Capri and the V6 Mustang and found very little or no gain.
"What we found was tremendous deterioration of the wrapped pipe. It rapidly oxidizes. In some cases, we found the bends distort and the crossover pipe warps. Once removed, the exhaust system cannot be reinstalled.
"For most automotive applications, wrapping is unnecessary, costly, seriously affects exhaust-pipe life, and generally is not attractive."
In both cases, George was referring to a V6 engine. On any V-type or opposed engine the crossover pipe takes the most punishment.
The book goes on with examples of other heat blanket foolishness. Anyway, IMO you should have only enough heat shield to keep the engine bay temps down. The downpipe won't undergo the same stress an exhaust manifold suffers, but a heatshield wrapped around the downpipe will lead to corrosion/deformation and it simply won't improve performance much.
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anyway, when it comes right down to it the supposed advantages are just a marketing gimick (IMO). I wouldn't pay more for them, and I certainly wouldn't want anything flying through my turbo.