for what its worth, i was in the local hardware store one day while the floor was apart in my truck. i got a roll of insulation for water heaters. four bucks and i had enough to do my pick up and a buddys camaro. it was basically foil on top and bottom with plastic "bubbles" in between. the label said it would withstand ambient temps of -75 to 325 degrees. it was about one half an inch thick and with the foil you could mold it to any shape you want. big difference as far as the noise was concerned and a whole lot warmer in the winter...
