I did use Hushmat on the floor. I put two layers on the firewall and the section under the pedals. A large (17" x 44") piece of 3/4" plywood goes between the pedals and the seats with the gear shift in the center of it. To make the floor flush with the wood, I used three layers of Hushmat. The Hushmat is 1/8" thick and I have been told that multiple layers work well. The metal floor is held in place with small machine screws that have round heads. I cut the Hushmat to fit around the screw heads in an attempt to have everything flat when finished. My truck did come with carpet but I wanted something I could wipe off with a damp cloth. The pictures show the floor behind the drivers seat and if you look close you might be able to see that I used many small funny shaped pices. I tried to not waste any. I also did the iner part of the door and the door panels that screw to the inside of the door frame. Smaller pieces are easier to use than large ones in tight spots. I drove the truck with no carpet or upholstery other than the seats and it was not bad. I hope the new door panels, head-liner and wall corner pieces help control the noise. Hushmat claims that it cuts the heat as well as sound.