Just the other day, I was driving around 60mph when one of rear passenger had the rear window put down all the way. After doing so, the whole cabin started to vibrate and resonate very loudly, it feels as though the car is shaking. Keep in mind, the sunroof was not open, and only one of the rear windows was open. I closed the rear window from the front and decided to open the other rear window to see if it did the same thing, which it did. When I had both rear windows put down, the cabin vibrates and resonates twice as much. After driving for awhile and messing with the windows, I determined the cabin only vibrates and resonates with either rear windows down when traveling around 40+ mph. I was going to have my dealership check it out. I was just wondering if anyone else have the same experience and what was done about it.