I have never used deadener, and want to put it in my 2006 Chevy Malibu LS. I am probably being too ambitious as I don;t know how long it takes, but I want to do all 4 doors, the floor, and the trunk top and bottom. I suppose I want to do the top of the car too, assuming the headliner is designed to be removed. I welcome any advice and I primarily need to know how much deadener I need. I plan to buy the AT60.
My goal is nothing special. I would like less road noise but primarily I would like my music not to be so audible outside of the car. I deliver pizzas and I have noticed that my stereo is audible at a customers door even when its at very low levels.. My stereo is basically loud at 20, dangerously loud at 25.. I listen at 18 when singing and 12 when rolling through a customers neighborhood to make sure I wake no one up and hear complaints. No customers complain when I'm at their door, but it's ridiculous that I can almost make out lyrics at such a low level.
EDIT: Also do I really need to double up anywhere. Is the doubling up just for the super flexible areas? The only one I can think of would be the roof of the car.