[70onB.A.D.'s]

What about doing bedliner on the underneath of the cab that way it acts as a rust preventer as well. And then do the dynamat on the floor of the cab on the inside. The dynamat is pretty strong we had a truck in out shop that had it all over the inside and with three 12's pushing hard and you could not hear anything outside and no noise coming from the outside when the system was turned off. Its just a thought.