(return and front) Camera for retrofitting?

Hello everyone, My original post is below – if someone already answers and quotes – I changed my mind after the reviews read at Amazon… These PDC systems are probably not very reliable on the one hand, on the other hand nothing for the wash road, which I very much like to visit. What I would like to do instead: a monitor with two cameras – wash road-proof. A contamination of the cameras is no problem – if they are not hidden behind a flap, then the I am looking for a system with a camera in front, and one in the back. Everything should be mounted on a SLK R170 in front ofMoPf, and the system should be switched on by switch – and not by reverse. In the front I want the camera for the narrow streets in Italy, and for our narrow underground car park. In the back it should be centered, and “large obstacles”. Does anyone have a product suggestion? Alternatively: an The front can also watch the woman if it is to go through narrow alleys :-In the relevant online shopping portals there are return cameras and PDC offers without end. I also have someone who would install it all (normal, free workshop). But…. I did not find a system that is COPPED with a camera. Can someone recommend it to me – which also works well? Alternatively…. Which PDC system would be recommended? (best system for small money) The optically identical system with sensors for front and rear is between 26 and 72 EUR on amazon. Which camera would be recommended? (best camera for small money) By the way, I would like a “simple” installation: I would like to switch on the PDC camera system manually.