Dang Dude, You work fast.
I like what you've done but my hunch is it could be improved. The length seems a tad long, you could build it shorter I think and get similar results. It looks like it may be cumbersome in the long run and foul weather, and I wonder about legalities with the covered rear lights and length.
I know Aerohed put a 3 foot (+ or-) flow collector on back of an old 67 (+ or-) VW Transporter van and improved its performance a bunch.
The shape seems to initially drop too quickly. The transition should be more subtle.
Here is my take on it.
The sides should curve in equally as well since a bunch of air is moving there too.
Also, if you're not using the roof rack, figure out a way to lose that, it can't be helping you.
Great Job!!
