First, are the tires scrubbed in?
Tire pressure will be very critical on xDrive. As said, rubber is softer and therefore will likely distort more than run-flat tires.
What is the front to rear pressures variation, you may need to adjust and experiment.
Straight running, as on the highway, will likely show wheel speed differences/interpret as errors, more than in bends etc., when DSC parameters will be different to accommodate manoeuvres.