I have a 2001 VW Jetta and I had a custom box built. If you fold down the rear seats you see the two 12's. I dynamatted the entire trunk. The problem I have is the back deck inside the car rattels on hard bass hits.(The deck that has the brake light in the back window) I put dynamat on the metal under the deck and this helped a lot. But I still want to stop this problem. Can anyone Please Help!!!!!