My old job had me commuting over 35 miles one way to work. Half of that time was spent with a carpooling co-worker. Despite having a *loud* soundsystem, and said co-worker enjoying music, I tend to be a bit shy regarding forcing my music onto other persons, so when he was in the car I would turn off the stereo. We didn't ride in complete silence however: all the plastic door lock posts *rattled* like crazy. Here I added adhesive backed green felt I purchased at Home Depot to various spots on the lockposts in order to silence this buzz.