There are several products available that will help with sound and heat isolation based on foil-faced matt. I used it with great success under the carpets in the BOSS car, and it's quite thin. Look in a Summit racing or Jegs catalog or online under 'carpet' I think mine was called Wonder Matt and came in a 4x6 sheet. You can use spray upolstry adhesive to glue it to vertical surfaces. Good Luck.
Here you go:
http://store.summitracing.com/default.asp?Ntt=tru-blip1...target=egnsearch.asp
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