Hi Harry I have fitted hard wired reversing sensors to my last 2 motors, had both kits of Ebay and gone for the sound type, both kits I used had good instructions and even a phone number if you needed help.
Fitting the sensors in the bumper are not a problem, once you have got them off the car, most bumpers even have the marks at the back to show you where to drill the holes. (Hole drill normally supplied with the kit)
The problem with the Sportage is connecting the reversing light feed to operate the reversing unit.
Not a simple job had to remove the side panel in the rear to get to the wiring lome.