I got some of the sound deadener stuff from dynomat. Got a really good deal on the big kit on Amazon (the whole car kit was cheaper than the door panel kit at best buy!) So far I've only stuck it around the rear speaker deck but it definatly made a big difference in the sound of the speakers. They're much clearer and bassier now. Only down side is it works so well it's noticably muffled the sub in the trunk...gotta do some figuring on that one... kinda hoping I've just got a wire crossed somewhere or screwed up the amp settings, otherwise either dynomat works EXTREMELY well or I've blown a 10" sub...