For $130 I can buy two really good quality 1080p dashcams and two 16GB microSDHC cards (I know, not the intended function of this...) and mount one facing forward and one to the rear.
You still have to run wires to power your dashcam and display video where the driver can see it -- that's what $500 buys, the need to not have to add wires to your car.
You still have to run wires to power your dashcam and display video where the driver can see it -- that's what $500 buys, the need to not have to add wires to your car.