I feel the Center of Pressure is close to where I show it above.
Cut the car out of the picture, transferred it to cardboard, cut the cardboard out, then balanced the image (like a see-saw) and it balanced on that point. Probably close.
Also since the car is flatter at the back than the front the point is probably even further back as the method I used doesn't take that into consideration. It gave equal aero weight (not sure of the proper term) to the cars shape as viewed from the side. A flat surface, as viewed from the side, would move the CP in that direction verses a rounded surface for the same surface area.
To work on that you could whittle out a small model to scale and put a pin through it vertically and move the pin to the point where the model didn't weather-vane around when you put air on it,
Sum