Can you replace p255-r70-16 tires with p255-r75-16 tires?

Yes, the 75 has a taller sidewall than the 70. If the car has stiffer suspension it will give a feeling of sway the taller you get.

Can you? Yes. Should you? No. Your speedometer will be off and your ride and handling will suffer. If you must change sizes go with a 265/65-16 or 245/75-16. My advice is to stick with the OEM size.