I converted my slightly bigger Isel by removing and replacing the steppers but using the existing wiring. Test the existing steppers before replacing however.
The existing toroidal power supply is a good piece of kit keep it. Several voltage outputs.
Your choice of stepper drivers.
I went for Planet CNC controller. I have Mach 3 and the Panet TNC is miles ahead in my experience.
It really is not a very difficult task. I have no electrical experience and managed this conversion with minimum help, most of which was confirmation, of what I was doing. This forum was enormously effective in guiding me to completion.