Adding the speed limit or cruise control function takes an
instrument cluster with the indication support. Also
switch unit steering column has been reported, although I don't see the options mentioned for it:
https://www.realoem.com/bmw/enUS/sho...diagId=61_5558.
I have the speed limiter function (and I don't think I have a combox: none of it's
requirement options is present in my car) but I never use it: it's uncomfortable to have it intervene, I recall cutting down the engine reportedly may bring down some (turbo?) engine valve leading to the infamous general drivetrain error and I do seem to feel the speed well enough (when I guess I should stop accelerating a glance at the speedometer confirms it's just the time
).