I looked into this when I ordered the G42 M240i for my wife. I was going with the M797 with all seasons but when I saw the rears are 225s with 8.0x19 wheels I changed my order to the performance tires which comes with the 245 rears which I’m sure has 8.5x19 wheels even if the order guide says 8.0x19. I will ask my dealer to order Michelin Pilot AS4 from tire rack on my dime and have the car delivered with them mounted. I will save the performance tires for when I sell the car.
The G20 4 series has the same M797 setups and it has 8.5 inch rear wheels for the performance tire option and 8.0 for all seasons. 8 inch wheels are too narrow for 245s and I would not run that mix.
So what to do in your situation? I would order two M797 8.5x19 wheels. They are available for the 4 series at $1300 for both rears.
https://www.alloywheelsdirect.net/bm...97m_wheel_6891
(You need to set front wheels to 0 since all for wheels are pre-selected)