Yep set up is depending on what you are needing, look at techmoans stuff on youtube he reviewed tons of them,everything from the single to a couple two cam setups. Answer a lot of your questions. I didnt do any GPS ones as i dont feel i need the functionality of it nor the ones that record the interior of car. I shut off the g shock stuff and motion, but you can wire it to always hv power and sleep and wake up on motion if you need that.
For me it was the no battery, 1080p, and auto record on power were my parameters. After you figure out what you are needn't to cover there is most likely something out there.
Lots out there just make sure to get it from a place where you won't get a cheap remake.