Sorry, but I can't help thinking that the air needs to follow down the back end on something to get the best return. That pressure building back in my mind is helping to push the car along. When you do it in steps, it just is not the same.
On my 04 Civic, it worked out to where the back end of the "Kamm Over Trunk" was tall enough for me to put in a 8" window....were I to get off my lazy butt and build it. This would have allowed me to put a small rear window on that would have allowed me a view straight back.
