I have the M3 LR 2023 model. I don't know what the "claims" are, but from experience this few months of driving it, I get between 13 to 18 kWhr per 100km. With a 77 kWhr battery (I have heard it has 80 or 82 kWhr too - no idea what is correct), the range you get will very greatly. The energy usage varies on many factors:
- Speed
- Acceleration
- Number of occupants and luggage
- Tyre pressure
- Temperature
- Wet or Dry road
- Night or Day
- Aircon running on Auto in background
- Your start and end height above sea level !
Probably more than above, so it may well be possible to get 600 km from a full 100% charge, but then it could be down to 400 km in less than ideal conditions. My average seems to be around the 550 km for 100%. But also remember you probably want won;t to drive down to 0%, so allow 10% left, thus the usable range drops back to ~500km on average. This is mainly metro driving 50 to 70 km/hr, plenty of stop/start.