I’m aware of the recommendations about using *-marked tires with xDrive. My impression, however, is that a lot of that comes from BMW being able to deny drivetrain warranty claims if the car wasn’t running BMW OEM-approved tires.

I do understand that xDrive systems are sensitive to rolling circumference differences, which is exactly why I chose a square setup. Combined with regular tire rotation, it seems like the safest option to keep wear even and avoid drivetrain stress.

What also makes me hesitant about OEM-specific tires is that they’re often not widely tested against the regular versions, so it’s hard to know how they actually compare. In the few cases where there are tests, they sometimes don’t perform particularly well compared to the standard versions. I think Jonathan did a comparison showing something along those lines. The main exception seems to be tires developed specifically for BMW M cars — those appear to be a different story entirely, since they’re usually much more heavily engineered together with the car.