Krosno, I know what you mean about the repairs - it was always something, and my GC only had 86K miles. I really liked the GC new model - until I drove the T4R! The fit, finish, and features of the Jeep didn't compare.
I purchased the reverse sensor on eBay - heres a link to a similar model:
Reverse sensor
The nice thing about this one is that the display is pretty small, and the gray plastic matched my interior fairly well. It reads the distance in meters, but I pay attention to the sound - it beeps faster as you approach an object, then a solid tone within 6-12 inches.
The kit I bought included a hole saw. I didn't have a problem installing the sensors, but drilling that first hole in the bumper made me a little nervous. They are black and don't look out of place on the grey bumper.
I ran the wires through a grommet on the drivers side and routed them into the jack storage compartment where I installed the control box. It was easy to tap power off the backup lights. Instead of mounting the display up front, I decided to put it in the rear, reasoning that that's where I would be looking as I back up. Total install time was about 3 hours, most of that spent figuring out where/how to run wires.
I've attached another pic of the sensor from the back.