Every car needs one of these..

[Arct1k]

Similar to the old Z1

One of the most interesting features of the Z1 is its unusual doors. These doors retract vertically down into the car's body instead of swinging outward or upward. The inspiration for these doors came from more traditional roadsters which often feature removable metal or cloth doors. Because removable doors did not fit within BMW's design goals, the retractable doors were installed instead.

Because the body, with its high sills, offers crash protection independent of the doors, the vehicle may be legally and safely driven with the doors up or down, although they are not legal in the U.S.

The windows may be operated independently of the doors, although they do retract automatically if the door is lowered. Both the window and door are driven by electric motors through toothed rubber belts and may be moved manually in an emergency.