If you are interested in which product is the best and the least expensive check out the link below. It is a comparative study of these products and concludes Dynamat and SecondSkin are equal with SecondSkin the least expensive.
http://www.sounddeadenershowdown.com/That's a great link! I read the whole thing, very enlightening.
In short the big question of quality and durability in sound deadening material comes down to asphalt versus butyl, and he recommends butyl quite strongly.
"If you really need to do this in the absolutely least expensive way and are not convinced or concerned by the demonstrated inferiority of asphalt based sound deadeners, go to Home Depot or Lowes and get a roll or two of Peel & Seal. This is the least expensive option and you won't have to worry about shipping costs. I can see no difference in Peel & Seal and the asphalt based aluminum skinned products in this review. If you are going to live dangerously, do it right. "
And if you read further he recommends the quality of the SecondSkin products over all others, and its reduced price when compared to "dynamat".
If the tables don't turn in the meantime I'll try some when I get to that point with my cab.
Grigg
