Yesterday I set out to kill the rattles in my trunk lid and to make it look nice. I filled the supports with Great Stuff; sprayed with 3M undercoating and covered it with Fatmat. After that I used some 3M adhesive spray to attach the carpet. Iâ??m very happy with the way it turned out. It hardly rattles at all anymore. Here are a couple pictures of it; I know they suck.