I'm coming at this as a person who has never handled the camera, and so these are suggestions from a real "newbie":
Anyplace in the manual that has a metric measurement should also include an approx English measurement in parenthesis. While I realize that the majority of the world uses metric, and that those of us in the US are significantly behind the times, we are also probably the worst educated. We only learn one language (barely) and one measurement system (that really makes no sense at all.)
Page 5 (installation): below the diagram of the cable routing, in a small font, add something indicating that the layout of the car would be reversed depending on region.
Also, in the same area of the manual, it might be a good suggestion to determine if the cable cover top (what is it called?) should be used and to ensure that the camera is mounted in a location that leaves room for that cover. It might suck to mount the camera bracket with intention to use the cover, only to realize that you mounted the bracket 1 inch (er.. 2.5 cm) too high.
Page 8 (Settings): This talks about setting the timezone... Is the timezone offset stored (and/or displayed) with the recorded video? If so, it would be good to mention that here. Some of us would rather set/leave a GMT (+0) timezone rather than fiddle with timezone settings twice a year. (I tend to do this with any electronic device that pulls GPS time, but doesn't set summer/winter offsets automagically.)
Page 11 (setting list with defaults in blue): The "Auto Restart" setting has a default of 1 min. It's documented as "setting to automatically restart the DVR if there is no active recording or power is interrupted during boot." The setting value is a time (or timer?) but I don't see how that description would have a time/timer value. Is it the time before the DVR restarts? How long it spends restarting?
Page 11: The "Screen Saver" setting has a similar issue as above. In this case, I actually understand the intention, so I can suggest the description to be "setting that determines the amount of time of no user interaction before the LCD display is automatically turned off."
Page 12 (buttons): The description of disabling the backlight of the screen is confusing. Does this function turn off the screen (the same as the screen saver) or is the screen still active, but just the backlight turned off? If the former, it should be simplified to just "turns off the screen display." (What good would the LCD be if not backlit?)
Page 15 (more buttons): In describing the fourth function of the MIC button (disable or enable audio recording), it would be useful to indicate if the setting made here is persistent or not. In many US areas, users might want to persistently disable audio recording for legal reasons. (I really, really, really hope it IS persistent.)
Page 16 (basic operations): #2, "manual recording".. this is confusing. It's titled "Manual Recording" and then says that pressing the power button will power on the device and being recording automatically. Is it manual or automatic? (I was expecting this section to describe the REC button.)
Missing: AV-out port should be documented. (Technical documentation so people know what to buy to use with it.)
Missing: power requirements for the miniUSB. 5v 1 amp? Many modern cars have USB ports dedicated for phone charging - those often provide 1 amp.
Perhaps add to the FAQ some info on the CPL filter option. (used to help remove/reduce reflected glare - available from the same distributor your DVR was purchased from.)
...another FAQ (that I've seen asked on this forum a few times): Include a diagram showing how to insert and remove the camera from the mounted bracket.