Today I discovered that driving the car with the sunroof completely open, the windows up, and the rear seats folded down causes an unbearable noise and vibration condition that feels and sounds like a helicopter flying directly over the sunroof. Not that it is windy, but there is a staccato buffeting noise and vibration that is exceptionally annoying. I have used the sunroof almost every time I've driven the car (unless it was raining) and became very alarmed by the noise. I varied the speed and noticed that this condition occurs between 40-60 mph, regardless of road surface. Below and above those thresholds, it seemed ok. Also, closing the sunroof partially stopped the noise as well. I pulled over and flipped the seats back up and things were back to normal.