I did not know it was that complicated OMG! To not complicate things, it's usually just me and the mrs in the car we dont have any kids. So just going by the sticker psi should do fine?
This is what it says in the manual for speeds up to 120kmh
Tire size Pressure specifications
in bar/PSI for the 328
F: 225/40 R 19 89 Y RSC - 32 PSI
R: 255/35 R 19 92 Y RSC - 35 PSI