I have installed a parking sensor kit in my car and it is working perfect.
My whole parking sensor system contains: a rear view mirror, backup camera(pasted on my license plate), and 4 sensors are fitted on my rear bumper. I did not try for aftermarket parking sensor before, ever seen my friends did a DIY aftermarket sensor, seems not bad, and the work function is in good condition.You may have a reference from:
http://www.espow.com/wholesale-car-e...g-sensors.html
My friends added a OEM parking sensor with several other items..It can be done with all OEM parts..The replacement bumper inserts with parkting sensors come Pre Painted from Mercedes..NO need to paint.