[Sirrotica]

It all depends on what you're going to use the car for.

If you just want a daily driver, then keeping the factory pressures will be fine. If you want the car more responsive, but also the ride won't be as cushy, then raise the pressures up.

Fuel mileage will increase, and rolling resistance will decrease as the pressures are raised.

If you were to autocross the car the pressures would need to go up for sure.

You don't mention what tires are on the car, but modern tires have a higher max pressure rating than the older tires did.

If it were my car, the tire pressures would be at least 32 minimum. I don't like the limp noodle handling that comes with sidewall flex of low inflation tires. The tire is a mini spring and just as air bag suspension stiffens with higher pressures, so does more air pressure in the tires increase the stiffness of the suspension.

FWIW, anyone using such a car for performance driving would use the tire pressure as a fine tuning aid to get the ultimate grip, and handling from the tires, and car.

In the end it's up to the owner/driver as to what they expect from the car, and tires, as to what they decide to run their tire pressures at.