Most of the aftermarket systems are more or less the same. The electronics are from China but I cannot find sensors cheaper than buying a whole kit - what I mean is the whole kit with sensors is really cheap. Most of them only go down to 30 or 40cm so I have just finished taking mine to bits, pulling out the micro and fitting my own, which I then coded, and changed the wiring to the display to a simple four wire. My min distance now is about 20cm which is much better. I used the old led display for distance but added a left and right bargraph too. The display is easy to power from the radio or cig lighter and in my version two of the four wires are supply to the reversing module which gets switched on by reverse. It does not get power from the lights (nasty) but senses the lights to detect reverse. Finally, my new display sits neatly in the oddments thingy under the radio. I only finished it today, but when it is fitted I will post some pics.