Looking at the 2025 configurator: Comfort Pack £1,575 (guess its £525 on cars that already have electric seats)
The Comfort Pack comprises Heated Steering Wheel, Comfort Access, Electric Memory Seats (sDrive20i only) and front Lumbar Support (sDrive20i only).
I wouldn't want the hassle of trying to research /retro fit any of that, even the wind deflectors are relatively expensive second hand. Its the extras that make this car IMO. I went to look at one at a BMW dealership that turned out to be pretty basic, glad I waited on for the car that I've got now. Must admit I looked at the m40i