what exactly is needed? I have an 07 x3 with the 16:9 nav mkIV without the tv tuner module.. is there an additional video module that's needed to allow a camera to be added? I've seen little 3rd party adapter boxes that let you splice into the screen's video feed but I would prefer something thats integrated and/or plug and play.. the tv tuner kit seems to be quite expensive and useless other than for the video inputs for a rear view camera.