There are compaines that specialise in fitting EPS systems, seen them fitted and they can work well if specified with vairiable controller rather than a fixed amount of assisatance which often gives an artificial feel, like the Punto system used to feel when using the "city" function which made it over-light in my opinion.
You can also get speed senstiive sytems that vary and lessen the assiatance as speed increases.
From the ones I've seen (fitted to VW T2 cameprvans) I personally would go for a manually variated one as once you get going above 30ish MPH it can be simply turned down to 0% assistance so it drives as before, but for parking etc the turn of the control knob gives a modern cars level of assiatnce, they do work well in that regard but as has been said they can lack feel under normal use.
https://easysteer.co.uk/
