i just purchased a dual dash cam *Viofo A129 duo..

Whats the best way to install this? there is a 2nd wire that connects the rear cam to the front cam, but im not familiar with removing the panels inside the car.

 

Was there a trim removal tool included? I believe you can just tuck the rear camera wire into the headliner using the tool to help you get it tucked up.

 

Personally, on the lady's IS, I ran the rear camera wire through the passenger side first through the headliner, down the a pillar, under the side sill trims on front and rear, back up the pillar and to the rear of the headliner and finally the back window area. I did this due to not wanting to mess with the whole headliner area and only knowing how to play with the 'give' on the edges of the headliner. The wire itself was well over 15 feet long so I had plenty of slack to do this, I had roughly 2-3 feet remaining after the install which I just tucked into the rear part of the headliner when lining up the rear dash cam.
No trim removal tools were needed, simply tucked and used my hands to get under a few grooves. I've run this setup for nearly a decade on other vehicles and have had zero issues.

 

This is an easy install with plastic pry tools used for smart phone repairs.

 

Power cable install (follow the red line and ignore my mad ms paint skills), because the only cig port is in the console storage your cable might not reach or it is literally extended to its max as with my Thinkware X500 is... I got lucky.
Along the way the cables are fit snug in to the liners, pockets and crevasses.
Use a cable management clip to secure the cable going into the storage console to avoid a passenger snagging on to it, this is only an issue if the seat is moved back, in most cases the seat will cover it anyways.

 

Rear cam cable, the only challenge I had was the cover that is between the driver side doors as I had to force the cable in with my fingers as its was tight but it is safe to do it with care.