Exhaust manifold wrapping

[CJ]

I was thinking of wrapping the exhaust manifold on the GPX with a view to decreasing underhood temperatures (and in turn induction temperatures), also, my understanding is that wrapping maintains hotter exhaust gases which in turn helps the gas to exit the system faster due to decreased density. My fear is that this process may crack the manifold due to the increased heat build up in the downpipes, has anyone any experience of this?

CJ