ATM i think the K2 might be the best option for side coverage, its meant for use on motorcycles, but i am sure it cam also be used in a car.
Its a dual channel camera so you get 2 cameras that record onto a single memory card, much nicer than having to go retrieve individual memory cards in each camera.
Our good friend
@niko up in Ireland should have them on the shelves soon ( it is a new product )
https://dashcamtalk.com/forum/threa...aluminium-camera-mount-and-dvr-housing.33980/
I am not quite sure what kind of parking guard the K2 will have, but as its the same hardware as some dashcams i assume that will be the same as those cameras too.
I have a older version ( single channel ) with sort of the same camera housing, you can see it installed on the back side of my right side B pillar in this video.
you can also see how my left side mobius are installed.
Be advised side windows dont have wipers so droplets on then can and will impair the view at times, it might be a good idea to use some form of repellent on the glass like rain x and so on.
One thing is for sure with this kind of application you will want cameras that have prebuffered parking mode, meaning you will have a few seconds from before the trigger event on video too, otherwise a car ripping off a mirror at speed, that you will never even see on a camera without prebuffered event recording.