I would use the dynamat type on the floor and the closed cell type sheets an the roof and sail panels. The closed cell stuff is the small bubble rap type bubbles covered on each side with a silver sided plastic. I bought rolls of it from ACE hardware. They can order the larger rolls from the warehouse.
For my Challenger, I went to the Lowe's carpet dept. and bought a couple of yards of the shredded type carpet padding. I glued 2 layers above my headliner.