i use Thermo-tec header wraps on most of my bikes to stop the "burnt drumstick" effect on my leg. i've never noticed an increase in power, and never checked if it actually cooled the motor, because i've never had an overheating problem. i've had meltdowns on my race bike, but that was from leaning the crap out of them and hoping they last 50+ laps...
i don't use prep sprays to combat rust, as our exhausts get so hot they'll burn off any moisture, and the stock pipe is such a cheap piece of crap anyway, who cares if it rusts? odds are, you'll need a new motor before your pipe rusts out.
i haven't tried the sprays, but one trick i invented to keep the ends from fraying is to squirt a thick line of Krazyglue across the wrap, then cut it after it dries. doesn't burn off and doesn't fray.
when i start the wrap, i make my first wrap a few inches up the pipe, not a close wrap, more like a spiral tail, then over wrap tight so you don't need a hose clamp at that end. looks cleaner in my opinion.
(and yeah, the motor's all crazy backwards, i know...
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