The ones that just replace the headrests are easy.(if your adept at fishing wire through your car) You usually only have to run ground switched power and constant power it can get tricky when it comes to how you want to play the audio through your car speakers because there are many different ways to go about it. It can also get complicated if you are not installing two stand alone DVD units and you want them to mirror what's on the other or what's on your DVD deck.
