In the second image, you can see the two dust streams which wrap around the C-pillar. This is mirrored on the other side. The car has sat for a few days and the streams down the rear windshield aren’t accurate to what it looked like when I first got home. Originally, it was clear. I noticed there is no dust on the rear wing. I believe these are clues leading to the discovery of the counter-rotating vortices that I’ve read about on most notchback cars.
On that topic, I wonder if C-pillar extensions could help guide airflow off the C-pillars as well as capture air better into the captured separation bubble ahead of the pseudo-fastback. Wow, that’s a lot of big words. The first image of this post details what I’m referring to.