Yep Sven the Mercury Merkur xrti. A friend had one back then and I got to drive maybe 200 miles. What a nice car. Fast even at high speed with only a 4 cyl 2 valve turbo 140ci engine. It must have had good aero.
I am going to move the flaps up from the original Mercury design and keep them flat. Imagine putting the tips of the foils so that they are in line with the tear drop template.
Here was my prototype of the Merkur design. I was able to run down the road noticably quieter with up to 57mpg, still running the power steering and alternator just like a normal car. Since removing the coroplast the car is more noisy once again. I put the fin on last fall and it was just falling apart.
The trunk is an essential part of the vw package we usually travel with the car packed fully. I couldn't see spending the effort to make a complete boat tail and end up with reduced utility.
The front end is going to be wedged. Stock it is vertical with almost no radii on any surfaces. I am probably going to make it out of foam with the holes for the headlights made with generous radii which will double as air intakes.