General Motors Corp.'s new minivan lineup will feature the first automotive application of a foam-backed carpet system utilizing Foamex Inc.'s surface modification technology, which molds and cuts a single piece of foam to match the three-dimensional pattern of the vehicle's floor pan. Foamex says the technology can reduce vehicle weight by 2 to 6 lbs. and reduce interior noise by four decibels, twice as much as conventionally backed carpet systems.