Let's look at this image, look at where the diffuser is, and where the rear wheel cascades are. It seems to me that the exhaust is surrounded by pieces of bodywork that dynamically lower pressure. The exhaust seems to be a high pressure center(remember density of air decreases as it's heated, although not it's pressure, quite the opposite really, otherwise we wouldn't be able to extract mechanical work from mixing gasoline with air and combusting it)
In this image we see Hurricane Igor, blue and purple represent higher relative pressure, orange and red, lower pressure. Notice how the eye is blue, but the area directly surrounding it is red.
I bet you could take the second image and superimpose it with the eye being placed over the exhaust in the first and it wouldn't be that far off from the truth if you could run a pressure map of the rear end of the car going 200kph at full throttle, although I doubt it would be as symmetrical.
Also look at all modern airliners, why are the exits of the turbines under the wing where the pressure is higher? Why not blow over the wing, where the pressure is low, maybe because it would cause the wing to stall?
The height of cultivation is really nothing special. It is merely simplicity; the ability to express the utmost with the minimum. Mr.Lee