Sound deadening material has been in use in the auto-sound industry for at least a decade now. I use to be heavily into this trend (no more thankfully) and what the material usually does is convert sound pressure into heat, then disperses it in the material. One of the most recognized names is Dynamat. http://www.dynamat.com/ The application usually only required a hot air gun (or hair blower) set low. the material would then become plyable to almost any surface countour, and is self adhesive. By deadening the road noise and outside noise source, Sound deadeners are used to enhance the effect of your stereo system without requiring more power amplification. There is absolutely no reason this would not work in your D. The hardest part is removing the interior panels for application. Caveat: The material does have some weight to it. So be forwarned when applying it to your doors. -Jeff Chabotte webmaster: http://www.88-mph.com