In all honesty, the only benefit of the foil backed underlay is that it weighs less to ship, but at the cost of the sound and heat deadening ability. That being said, if you really want good sound deadening and a better heat shield, your best bet is to go with the Hush Mats. They are not form fitted, so it takes a bit more work to install, but you will end up with much less road noise and better heating/cooling of the passenger compartment.