I'd noticed some silver-colored adhesive insulating pads in
   a Griot's Garage catalog, unfortunately they are out and do
   not expect more. I wondered how well the "Roadkill" stuff in
   the VW magazines would help insulate ye olde Transporter?

>     trucks, big rigs, or tractors, as in tractor trailer.  Anyway, this
>     material was used along with an adhesive which was used between the sheet
>     metal panels and the frame of the vehicle.  This combination was said to
>     reduce vibration and noise considerably.
>
>     The foam was available in different thicknesses from, as I recall, a thin
>     sheet, maybe 1/16" to 1/2-5/8" or thicker.
>
>     I'll keep looking for a source.
>
>     Pat S.