A few years ago I fitted electric power steering to my ‘82 BMW, using a Corsa column and drive , bought on ebay for around £50.
If you have good engineering skills and some machine tools, this can be a challenging and enjoyable project.
I believe there are new options for speed variable sensing, use gps.
The whole job only cost around 80 quid or so, it transformed the car, making it a pleasure to drive.
Photo shows the project in process, more info available if needed.
cheers
Mike