I am planning on installing the Kicker speaker upgrade. I've seen a few photos and remarks about using sound dreading material like Dynamat to improve the sound quality. My question is how much to use and where to best apply the material in the doors? I found the Dynamat material at Best Buy locally but at $40 for 4 sq ft it looks like an expensive process. On the package of Dynamat it recommended covering the entire inside of the door replacing the waterproof door barrier. I've seen some posts where someone used a product from Home Depot. I have some of this insulation and the foam does not appear to be as heavy or dense. Will it still work?