Yes, the rails can be retro fitted. But at a cost. £600 for the rails alone. I know BMW like to make money but come on. They’re a £300 option when specking the car, and I know it’s easier to install during main assembly, but twice the price just for the parts!!
At this stage and unsurprisingly I’m going to pass.
It’s a common theme across all manufacturers. Some years back Motorcycle News ran an article where a brand new Yamaha was about £3k but bought as spares was over £11k.