I just finished my rear door. I will let most of the video explain, but I thought I would add some things. The front door has 3 layers of the other product (I wont name names but it is HIGHLY recommended on this site) in all accessable areas and the area that were too hard to reach have 1-2 layers. The front door also has the door panels "deadened" with the same crap. Now, the rear door has a single layer of Second Skin and since I have no speakers back there I didnt even provide full coverage throughout the door j, just the easy stuff to get to. I am VERY VERY impressed, the door feels rock solid now.