Not had mine done yet, but mean to get it done over the next few weeks. Full touch screen, bluetooth, google maps, etc without losing any original vehicle features.... cameras, hard drive, theatre surround blah blah. I believe it functions through the video port on the head unit. With a little software box canbus unit. Only trouble for me is the 4 hour drive to Birmingham! They do sell a DIY version that you fit yourself but touch screen doesn't work, you get a wired joystick controller..... £230 I think, personally I want the touch screen mod.