After experiencing an 80% hearing loss from driving my truck from Colorado to California, I used Dynamat when I stripped and painted it. Sticks real well. Covered everything I could. Inside of the doors as best I could, fire wall, floor all the way back to the fuel tank, over the fuel tank on the back wall under the rear window. Much quieter and cooler. I then installed a big foil covered carpet pad in the floor and firewall area, then installed the carpet kit. Had some Dynamat left over and thought about putting on the underside of the hood although I'm not sure why. I bought it at Al and Eds Audio, a local chain and it was very expensive. If you ask me it's nothing special. Just some kind of tar like substance with a foil backing. I wouldn't hesitate to use some other similar product but I was in a hurry at the time and just wanted to get my project done so I drove to their store and bit the big one. I spayed my bed (dump bed not a wood pickup bed) with a bedliner product. It's a globby paint and doubt it would have much in the way of sound or heat reducing properties. Then agin, I'm pretty new at this stuff...
