One of the features of the HUMMER HX ethanol-ready concept is a number of very configurable body panels. Doors, fenders and much more can be taken off and change the look of the vehicle to suit the fickle mood of the hypothetical owner. On each day of the Detroit Auto Show, GM will be showcasing a different look for the HX, and we happened to be walking by earlier today when the switch was happening. You can see a schedule of what's coming in this picture. Actually, now that I look the list over, it seems the version on the floor today is really supposed to be here on Thursday. Anyway, the point is you can change the look of your car. Which one would use to be most aerodynamic and minimize fuel consumption when you're driving?