My first post but have , I think, an interesting story. Never had any start problems in two years of ownership until had dealer install parking sensors. Subsequently, have had to use exterior start assist several times. I now have a battery tender hooked up when parked at home and also purchased an Instant power jump starter for any start problems away. Returned to dealer for assistance. After 6 hours of checking sensors, etc, they could find nothing wrong??? My wife is the principal driver of the BMW and I had the backup parking sensos installed for her benefit..