I've posted this before, but here's the tufted flow over the rear window of a Prius without and then with a lip spoiler:
Here's another, of the flow over the A-pillar and side window:
(Enjoy the scenery of the lovely Midwest during corn harvest season).
It's better than I expected; there appears to be some intermittent separation just along the top edge of the window, but overall the tufts point back nicely. Now I'm curious what it would look like with the mirror in place.