Right before I got my MS in 2014, I sold my BMW Z4 to a guy from Canada. He flew down and drove it back, no problems.
Well, except before he came down, he asked me to confirm that the car would switch into KM mode, which I went out to check. I turned it to KM mode, and everything converted to Kilometers. Immediately, the service indicator for the brakes lit up -- BRAKE SERVICE NEEDED. I'm assuming that this is an error/bug in the BMW code since the "mileage" went up, it triggered the brake service counter to be due. Even though the brakes were fine, I had to pay for a brake job (just pads) to reset the indicator, cost me about $200 I think that I didn't need to spend.