I am using a Boyo camera I got from Crutchfield and I’m quite satisfied with it. It came with a bunch of hardware for different mounting options. I mounted it to the underside of the hatch spoiler, which while giving a great FOV, isn’t an ideal perspective for the backup guide-lines. I was running lines for a Sirius antenna thru the spoiler anyway and had it all taken apart (read: I got lazy). Running it to the hatch lip like the pic above best location for sure.

Not sure about other makes, but the Boyo has a guideline functionality that can be bypassed if your receiver has the same. Resolution is great and it works seamlessly with my receiver. I put the relay trigger in the left cubby and tapped off a fuse with a fuse-tap.

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Current
Original owner 2002 E53 X5 4.4i to 4.6i swap
2026 G80 M3 6 spd
2025 G06 X5 50e
Former
1972 Audi Fox
1986 Saab 900S
1996 BMW Z3
1998 BMW E36 M3 Sedan
2004 BMW E46 M3
2006 Audi A3 Quatro
1993 Mopar 318 Jeep Grand Cherokee
2015 V6 Jeep Grand Cherokee