I actually just used something similiar to Peel and Seal last night. I got it at home depot, and it has some type of fiberglass in it to add additional support. I had a HUGE issue with vibrations in the tail gate from my subs. Got 75sq. ft. for around 50 bucks. Only put one layer on so if I didn't like it, I could take it off a little easier than 2 layers. Haven't really heard it from the outside yet, but oh man does it sound soo much better on the inside. Bass is a lot cleaner and hits harder. Now I just need to find some way of reducing the roof flexing. I had to take off the cross members of the roof racks since the sheet metal was flopping against them.