I installed a Prius electric power steering assist on my 55.1 and it works great. I chose the Prius because it appeared to be the smallest dimensionally. It is a three wire unit. One positive cable, one negative cable and one activation wire. I have attached an image that shows the size of the unit installed. From the engine compartment, it still appears to be stock. The cables come with the unit. There is also a module that activates the system. I added two couplers, one above and one below the unit. I used a newer steering column above the unit so I could upgrade the turn signal and emergency flashers with a new wiring harness.
