[Gilgorm]

My 2010 accident in my retired E60 was not as major as yours ($14,000) but the entire left side and both bumpers needed some sort of replacement or repair, along with the replacement of half of the rear suspension. I insisted the auto body have my BMW dealer check the car to verify it was at factory specs. They paid the cost (i.e. Insurance paid).
The good news for me was that the repaired car behaved and drove exactly as it did before the accident (high speed, three complete spins and two impacts). I owned the car and kept it for 2.5 years. My wife and I were completely unhurt which we attribute solely to the car.
I may be the only one to experience this but the repairs were superb and I hope your experience during your lease is both enjoyable and uneventful.
Good luck.