Heat sheilding??

[Mazdabater]

First off I'm sorry for the rough description, pretty sure I have seen this on a couple of cars and have been trying to find out what the stuff is, it's like an aluminium blanket with fibreglass in the middle insulation material. Looks like it's reasonably rigid though.

Basically what I want to do is get ahold of this stuff, so I can build sort of a box around my turbo, exhaust manifold and dump pipe out of it so it blocks all the heat for escaping into my engine bay. My theory is lower engine bay temps = lower intake temps = better everything. Would also give the cops less to look at when I end up getting pulled over for an RBT which 99% of the time ends up with, can we have a look under your bonnet over here.

Does anyone know what this stuff is called and is this a good/bad idea

Discuss.