@beginer Try this one:
https://www.racedepartment.com/threads/assetto-corsa-car-setup-guides.99049/
But some info there seems to be incorrect/outdated (e.g. GT3 tire temp ranges are completely wrong - no way softs are OK at 100C).
Actual working ranges (where tires stay within 99% of their peak grip) are more like:
softs - 65-90C
mediums - 75-98C
hards - 78-107C
Ideal pressure for GT3 tires is 26 psi, though sometimes you can opt for significantly higher pressures to keep soft tires from overheating (just a bit, won't help if they massively overheat), because they go downhill after 95C pretty fast and you risk to lose your car in the next turn. Generally, the lower the pressures the more tires heat up.
One more important thing is aero stall. If you drop your car too low your front splitter or rear diffuser may stall and lose downforce (e.g front on braking or rear on acceleration). It can also happen for a moment when driving over uneven surfaces like bumps or curbs. This changes the balance of the car pretty significantly. One way to see if it's OK is by telemetry and Race Studio Analysis software. If you see GREFF 1 (front splitter) or 3 (rear diffuser) channels showing something like this (especially the bottom graph), it's stalling and if that happens at a place where you need this downforce (in a high-speed turn) you need to raise the car or get stiffer springs.
View attachment 448166
Oh, and one more thing: somehow negative rear toe works in AC even though the guide tells you not to bother.