I have been playing the game a lot, and I have noticed that race tires don't do anything. Drag tires do, tire widths do, but not race or any other compound. I hope this is changed in the future.
I just took two identical cars, both the Bolide Notte, one with Competitizone racing tires and the other with Veloce sport tires. The car had little to no difference in handling.
Well alright, I was just testing you. The devs already have confirmed that the advanced compound physics will be there in the next update. So just hang on for now...
https://www.beamng.com/threads/tire-model-potential.38123 This thread might be of interest to you. It talks about the upcoming tire model updates, including ones that should potentially solve this issue.
Actually the current released Bolide pulls ~ 1.03g average on the skidpad with the Grip-All tires, and around 0.93 average on the Veloce tires, not only that but they achieve that peak grip at different slip angles too, so thanks for the suggestion but we got it covered