Just picked the most recent copy of 4wheel and off road and there doing an article on converting a new jeep (brand new) and with a kit, turning it into a pick up. In the process they are disassembling and seperating the brand new sheet metal and in the photos and captions they show where jeep has used a large amount of this automotive foam between the panels to fill some of the voids.... very interesting will do more research and see if i can get some answers.