www.fatmat.com
I used it on a restoration of my wife's 66 Mustang. We used it on the floors, the whole roof, along with the rear pillars. When we role up the windows you can have a conversation without raising your voice. We also drove it in 80 to 100 degree weather (no AC) and it helped keep the heat down in the car, much better than before. It comes with a roller (for applying it), a knife, instructions, and 100 sq. ft. (two roles) of Sound Deadener for $125.00. I have another 100 sq. ft. ready for my stepside to help with the noise. Make sure you use the roller or your hand will look like a smurf's hand. You just roll it on and you don't need a heat gun or any other tools besides the roller. My wife installed it and said it was really easy.
Sorry, have to edit, $125 is with shipping included in that price.