on my back left door, i noticed quite a vibration, caused from the bass from the speakers. i took the door panel off and smacked the top of the metal door (underneath the panel) and there is a clear vibration from the metal that holds the window and pulls it down when you push the button. It's starting to get on my nerves...it's really loud! i did the same pounding test on the back right door and it doesn't make the noise. something my warrenty will take care of if i bring it to the dealer??