I'm redoing the entire interior of my car. Removed everthing and then had a friend patch some of the floor board panels and the firewall. It's now down to bare metal and I'm considering one of the new overlays before I put the stock interior back in. I found a product that seems very appropriate as it has thermal and sound barrier characteristics. It's called B-Quiet. It has an aluminum sheet on top and a thick sticky rubber/asphalt compound. When you peel the paper off the back it sticks like...well, glue. I tried one of their samples and it seems to work great. Only consideration would be odor from the asphalt content if the car sits in the heat too long. Anyone have any experience with this stuff?