No amount of tinkering will get pCars to AC level of driving physics and feel: AC is used by Ferrari to develop road cars, by Porsche to make simulators for its customers and by ACI CSAI official Italian racing school for single seaters at Vallelunga (F1's Daniil Kviat is their graduate and also raced AC sim while there
https://forums.overclockers.co.uk/posts/26015583/ ).
pCars is a good game, but never comparable to AC, despite what Ben Collins & Nick Hamilton (who were paid to market it) say. iRacing, rFactor2, AC - in no particular order - are comparable sims; pCars is more inline with the Codemasters stuff and EA's NFS:Shifts