this is an EXCELLENT point.... i never thought about this...

i suppose wrapping PRE turbocharger exhaust is a good idea, to keep heat in, as 80 or so percent of turbocharger spool up is based on heat, and the rest is exhaust flow...

but wrapping after the turbo might be useless, as you might want to get all the heat out ASAP, as well as exhaust gas....

this hopefully gets interesting now