Start a test session and open up the DEV Apps 'SusTelemetry' and 'Car engineer.
You'll notice in SusTelemetry that the red lines are hard up against the yellow lines, this means the car is running on the bump stops!
The spring rate of the bump stops comes out to 3.9hz front, 3.3hz rear, against 2.4hz at both ends for the springs only. Which now that I think about it is not that far wrong, as in you could spring your car this way it's just that you never would. Hence why the car drives alright, but this'll need to be fixed along with CoG which is below the wheel centre line.
I may pass this along to the author if no one else helps him out soon.