Yeah, 3.5 is over most performance tyre's recommended limit.
Correct tyre pressure depends on the tyre, the load, the use and the road temperature.
But just for a daily driven car, most tyres will see even wear between 2.0 and 2.3 bar.
Lower pressure gives slightly better grip straight line and will be more comfortable.
Higher pressure will see slightly better economy and crisper turn-in.
Play around and see what suits you.
If you load the car for a trip, ramp the pressures up about 0.2 bar.
Good luck