Wrapping the pipe not only stops your boots from melting but also keeps heat in the chamber.

This may be a good thing depending on other factors, but you may find that you need to rejet to suit, as a hotter pipe basically acts like a shorter pipe as sound waves travel faster as the temp goes up.

What this all means is that the pipe will then be tuned for a higher rpm, so you'll find that the engine becomes a little more peaky. Depending on how much of the pipe is wrapped of course.