Cockpit camera shake
When using the drivers eye cockpit camera it seems as if the camera shake setting only effects how much the cockpit is moving across the screen. No matter if you put the setting at 0 or 100 the road ahead shakes like crazy (especially on bumpy roads like Kenya) and it makes my eyes really tired. This is caused by the drivers eye being attached to the movement of the car. This sort of makes sense as we are located in the car. In real life however your body/eyes/brain will filter/dampen most these small vibrations out as your eyes are more or less "locked" to the road ahead. When you look ahead and go over bumps the horizon you focus on is perceived as fairly steady.
Basically in real life you are moving but your image is not as your body compensates the movement and in this game (and DiRT 2.0 is even worse) you get the opposite where your body is not moving but your image is that you can not really compensate for. I understand this is to emulate the bumps but this would also be achieved by only having the cockpit bounce around while the road ahead is more fixed.
The camera shake setting should have a fixed cockpit and moving environment on 0 and a moving cockpit and a somewhat fixed environment on 100. Maybe add a little bit of (adjustable) 'lock to horizon' from the drivers eye camera.