During Christmas Break ('01-'02 school year), I soundproofed the car. This involved completely stripping the interior (removing all seats and carpet) and glueing undercarpet foam underneath. I did the entire interior except the door panels (I hope to get around to those sometime soon). As for now, it has already helped quite a bit. Usually, on the highway, I had the radio volume at -34, now I can hear it fine at -42. Not too bad, still a lot better than paying $300 for a Dynamat job.