[Piwoslaw]

While inspecting how dirty the car is today, I noticed a tiny detail on the rear lamp:

Can you see it? It's the thin vertical line of dust, just left of the center on the picture. Nothing fancy unless you know that this is the point at which the airflow starts to separate, that's why it's relatively clean ahead of that line. Here's another view:

So what? Well, maybe I could glue clear plastic at that point, extending a few cm to the rear. This would create a lip or minikammback with a sharp trailing edge. I'd do the same to the rounded corners of the rear bumper. Probably not worth any mpg's, but who knows?