chriskuipers

dynomat works great its just kind of pricy but its worth it

crxtuner

Elementaldesigns.com edead v1se, its kinda like dynamat but way cheaper and doesnt have a sharp foil backing that will cut your hands up. I used 40 square feet deadening/sealing my front doors for better mid bass response(using phoenix gold rsd65cs component speakers) and the final product had me finding any excuse to get out and listen to them. Also you can use the coupon "edeadba" for 20 percent of your purchase/