I think there might be a issue with the OBD dongles, mine did work but data have stopped working now.
Yeah you cant really have the main unit out in the open and have a neat install also, all those wires will make sure of that, a remote touch screen would be the ultimate solution for that problem.
But that would almost double the price of the product i think.
I would quite like the OBD data displayed on my dashboard, because I have had to unplug my 12 year old OBD display that was plugged into the OBD port, but with so many wires connected to the display it is very hard to do anything sensible. Most of the time the OBD display is pointless, but it did warn me when my alternator packed up last week, without it I might not have got home and I wouldn't have known that I needed to fix the alternator until I found the car wouldn't start the next day, instead the postman delivered the replacement part the next morning and I had it fixed by the time I wanted to use the car; I also watch the coolant temperature with it, and sometimes I watch the fuel consumption data.
I think probably I will not use the OBD dongle and hide the DVR.
A remote screen would increase the price, don't think it would double it though, and for people who are prepared to install all these cables a small increase in price to get a nice install might be preferable.
I am still firmly behind the "remote" cameras being the way to go.
Dual remote seems a sensible solution, but the Viofo A129 dual camera was much easier to install, only 2 cables needed.
And today I received another dual camera, which only needed 1 cable, and being mini USB powered I already had a cable available so I just removed the 3M pad plastic, stuck it to the windscreen, plugged the power cable in and it is working, and giving me video of front, back and most of both sides
OK the rear and sides are not as good as a 4 way remote camera, but it was easy to install while I still haven't worked out where I'm going to install my K2S.