Active steering - retrofit?

[Davidf]

Both my '04 E60 and my '08 E70 have active steering. I love the feature and miss it when I jump in my '98 E38.

To the OP, Active steering uses an electric motor and planetary gear set. I don't think the hydraulic pump is any different than that used on normal steering (not to be confused with active roll stabilization). Anyway the electric motor and planetary gear set are part of the rack and pinion steering gear and located at lower end of steering shaft. The electric motor acts on the planetary gear to change the steering ratio.

I see someone listed the pump as specific to active steering, but I don't see why it is needed unless one of the hose ports is in a different location for clearance/connection purposes. Or, because active steering comes packaged with roll stabilization and the roll stabilization would require a specific pump.