Hi Scott,

There are two main advantages in using the exhaust wrap. One is as a
means of reducing under cowl temperature, the other is performance. By
keeping the exhaust temp in the pipe instead of radiating out, the
exhaust gas speed is higher which aids extraction. That's why you
often see it on race cars and bikes. I have used it on race bikes and
it definitely shows up on the dyno (around 2 bhp at the rear wheel on
a Harley), and I have used it on my Rotax 912 aircraft engine, and it
has been on the stainless steel exhasut system I made for over 9
years. It certainly keeps the undercowl temps in check, and I haven't
had any cracks or breakages in 500 hours of use.
Having said that, I don't know if I will use it on the thinner and
much more expensive Vetterman exhaust that I have fitted to my nearly
finished Lycoming-powered RV6, so it's your call. If I had made my
own exhaust, then I probably would use it.
Cheers

Martin in Oz