Do you think this "Fuel Saver Module" is legit?

If you're interested in saving fuel, what I've heard alot about is "improving your driving habits." The best way to do this is see what you're getting all the time for mileage with something like a Scan Guage. That way you can see what you're getting at different speeds, throttle settings etc. Unfortunately they are not money saving devices at $160 shipped.