what are you planning to do on pressures? increase contact patch with lower pressures thus increasing grip and lower tire stiffness and vice versa with higher pressures?? also take account of tire wear variation with pressure if you didnt already...
After you have done this, are you intrested in improving engine, transmission,etc calculations because it seems like the hardest part is tires?... for example the turbo model for which boost should be proportional to intake pressure not RPM.
