[MTrenk]

I guess I should have been more clear. A rear wing will not become effective until around 50-60 miles per hour, unless you have designed the wing to stall at lower speeds. However with an underbody, you can stall at speeds around 20 miles per hour, and the effects only increase with speed. At 70 miles per hour, the rear wing (unless designed as such) will still not have as much effect on the aerodynamics of the car.

The point is that this information can be used for multiple design strategies, including economy. It's not backwards info for you guys, it's info you can use. 1000's of man hours go into designing underbodies for both racecars and extreme eco cars. I guess what I'm trying to say, is with a proper underbody for an eco car, you can see results at low speeds that seem rather ridiculous. I hope that clears things up.