I went back into past posts looking to see if we'd shown this. I gave up @ 9-pages.
Anyway, if you haven't seen this, it's worth a look.
You'll notice in the smoke flow imaging that, air is fully-attached at the aft-body top, rear separation line which validated their CFD results ( the reason for their trip to the tunnel ).
Then, the numerical CFD color image is presented, showing identical flow, plus illustrating the wake structure.
Annemiek Koers makes the comment that, had the rear slope of the roofline been steeper, they'd have lost flow attachment, creating a lot of drag.
The pressure recovery pushes the car forward.
Flow is separated from the diffuser. Which may have been intentional. Don't know, and while they speak of lift testing and stability, they do not go into it.
They speak of 'targets' and my take-away is, that they met, or exceeded them.
https://thedriven.io/2019/10/30/ligh...rodynamic-car/