Just left BimmerSports. I was very impressed with their crew and know-how.
A quick diagnosis by them verified that the x5 was 'clean' but needs the following for a CERTIFICATION:
brake pads, front and rear
Upper Control Arm bushings
Cost: about $700 with labour
They suggested an oil flush and that I replace the oil level sensor.
cost with labour about $500
$16,500 AS-IS (you do the above work)
or $17,500 Certified with oil sensor replaced.