I called dB Engineering about their sound proofing mat and got this info:
1" mat w/ mylar film 54" wide, 10' roll $83.25
Adhesive(caulking tube type) $5 a tube
3" x 30' mylar tape for edges $11.00
They claim a 45% reduction in sound. I plan to try it under the hood soon!
http://www.800nonoise.com/
1-800-nonoise