It will require sensors in rear bumper, wiring, modules, mirror cover, coding.
Damage, I would say about couple thousand before labor.
If you have a good driving habit, this feature is useless.
If you don't have good driving habit, this feature will make you lazy driver and maybe a dangerous driver.
I had it in my F15 X5, F06 650GC, G30 540i, and even my 958 Cayenne. To tell you the truth, I barely noticed it since I don't normally rely on it.