A few other good alternatives are:
HUSHMAT
LIZARD SKIN
The Hushmat is black rather than Silver so it can be hidden better. The Lizard Skin actually is applied via spray gun and has no fumes. They also sell a ceramic treatment for heat that can be applied first- with the sound deadener on top of it which is nice. Best part is, you're not having to cut little pieces to get them inside the tight spots. This stuff can be applied to the smallest areas for great coverage.
Hope that helps!