Don't mean to sound thick but is this a safety precaution from the extreme temperatures of the exhaust or does it do a job??

Cheers Steve

 

Heat wrapping/ceramic coating of your headers/uppipe/turbo keeps the heat out of the engine bay and in the piping/turbo to aid fast turbo spoolup. Wrapping the downpipe helps keep heat out of the engine bay.

It's a win win situation.

 

it keeps heat inside thus not in your engine bay/air intake.

 

That does make sense guys thanks for the comments