Do you want to be able to roll th windows down again?
Both products have their good points and their specific uses. Dynamat(DM) is a topical (surface) sound dampening layer, while Expanding Foam(EF) is better suited for filling voids between surface layers.
Both products will accomplish the same end result, but in totally different ways, DM cancels surface resonance by absorbing the energy in a vibrating panel, while the EF is designed to fill a space, basically connecting the two panels together, transfering the resonant energy from one to both, spreading it out so it is less noticeable.
The choice as to which way to go is going to depend on the amount of money that you want to spend, and the amount of work you're willing to go through. The DM is way easier but costs alot more. L8, Mike
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i discovered something that works real good for filling spaces in doors and stuff.... "carpet jute" ...heat shield. after i removed my old rubber carpet there was some under it. after i put a layer of hitemp mastic on my tail gate i figured id need to put something inside of it and i remembered that stuff i had laying around. well it worked perfect, if i knock on it from outside i get a dead thud and i dont hear much road noise thru it. so now im putting the stuff in every nook and cranny i can. hope this can help. ~chris
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