My car rattles with bass up high. But, I run my car off road a lot, so I don't think getting the stuff soundproofed just to later have it come loose again is worth it. I figure, turn up the radio. Dead Link Removed
Honestly, rattles from my car come from the housings of the door speakers, from the back cargo area behind the plastic, and from my power trailer brakes controller on the dash. But again, I guess it depends on how much patience the owner has to deal with it. I have a lot of patience, so it doesn't really get to me.
Adam