Yes I have. It is very interesting. They started with Cd 0.288 and I'm wondering how low they could have got if they had started with a 3L model with Cd 0.25.
Also your post on another A2 from Finland has been inspirational:
http://ecomodder.com/forum/showthrea...-fe-26651.html
Not to mention your Lupo.
I like the rear box cavity idea. I tried to measure how long the box is, and by measuring the side of the rear spoiler I got 6" is exactly the bed size length the 3d-printer I use. I would love to have something real to 3d-print to keep my motivation up when learning how to use the printer.
I already have some aluminium sheet waiting for me to get motivated on making the flat underbody. Maybe next summer when it gets warmer.