Yikes! I am working on a high end car audio install as we speak- one of my main reasons for the sound damping. I suppose I need to include the roof in my install plans also then. It would be much easier to do it when I do the rest of the VX, and it sounds like I'm going to want to do it.

As far as holding in heat, does it generally work as an insulator? In other words, will it also hold in the cold if I'm using the AC?