The Pacejka model isn't the end all, be all either. GM and older Pratt and Miller fits use piece-wise functions to fit the tire characteristics.
Those work really well too as the tire steady state response is generally able to be categorize as linear, transitional, or frictional for where it is on the curve.


Bill your steering compliance fit might be representative of some of the FSAE cars I had seen in my day, possibly even polite at that.
You are just missing the +/- 8 degrees of on-center steering lash.