This suggestion is more aimed at the UI than maybe the game itself.
The cornering graph allows you to see if the car understeering or oversteering. The blue line is the front tyre grip, the red line is the rear tyre grip. Tell me if I’m wrong.
Now that graph is way too simple for all the suspension settings we have. It would be nice to have a graph that had the handling for the turn-in, under braking mid corner and corner exit.
The turn-in being the initial turning and resistance to it. Under braking is cornering while braking and this would also be useful to check the brake bias. Mid corner is what is already displayed(i think) which is cornering on coast. Corner exit is cornering on full acceleration.
Why? Because it would allow to have for example the fun class divided from the pony class by the way the car handles.
Thoughts?
“The cornering graph allows you to see if the car understeering or oversteering. The blue line is the front tyre grip, the red line is the rear tyre grip. Tell me if I’m wrong.”
You are wrong. 
The red line is “neutral” steering behavior, the blue line is “moderate understeer” steering behavior.
If you place the little circular marker on the red line you usually get the best sportiness, when you place it on the blue line you get the best drivability.