You can choose the version with a rear camera too, comes with a long cable to route the wiring etc and it all feeds into the same bit in that housing.
This is it for ref for the E46, but same ones exist for other cars too:
Smarter Shopping, Better Living! Aliexpress.com
www.aliexpress.com
It has Wifi built in and using the Viidure app to connect is quick and easy, you can then view or download footage as needed, or just eject the microsd card etc.
The app:
Here is some footage put together for day/night driving.
As you can see it's acceptable given it's the lower 1080p H.264 sensor not the 4K WDR one using H.265., and yes my windscreen does need to be cleaned. I think what I will do is order the 4K one on its own and just swap the camera section out and sell the 1080p one on one of the E46 groups for cheap. A bit of a loss but at least I know the system fully works as expected.
Note that it does not do GPS or other super fancy stuff, plus I don't really care about displaying my own speed
It just records and timestamps the footage and has a crash sensor. The time/date is synchronised from the app.