Kudos for your well thought out work on a sedan Kammback. I am sure many of us are hoping you can log some good fuel mileage data over the long weekend. Do you have similar highway mileage data that you can compare to, with trip conditions as close as possible to your new data? I am eager to see if you notice a significant, measurable increase in fuel mileage at highway speeds with the partial boattail.
Also, I couldn't quite tell from the pictures if the clear top part is still hinged to allow access to the trunk.