You can replace the padding with felt carpet padding from HomeDepot or
Lowe's.  It helps cut out the high-frequency sounds, like hissing and belt noise.
Get the felt stuff, not the foam.  For lower freq stuff, you gotta go with the
sound-dampeners or the flat sandbags you get off of some junked cars.

Check out Matthew Bulley's pages at <http://www.bulley-hewlett.com/VWindex/>

Bill Marshall
85 GL Tiico "Pandora's Box"
Aurora, IL