I have the same problem too. When you close the doors with the windows down it sounds really bad. Makes the door sound like a cheap piece of $hit. Aren't there two plastic tabs that attach to the window to control vibration. I haven't taken the panel off yet, but I'm almost positive there are two plastic tabs that can break and cause the window to rattle. I have the rattle on both doors now. I'm just going to take my car to satan (mitsu dealership) and tell them to fix it. It is one of those little everyday things that can drive you to absolute insanity.