Info on TV Tuner on Touareg

    Sorry if I write in English but I'm Italian and I don't speak german.
    I write here because the Tm-techmark suggest me to post here my question.
    This is the story: i've ask to my VW dealer to install the TV on my navigation system, and they told me that they have to change all the navigation with a new one for a total cost of over 6000 Euro. I've look in internet for some TV tuner and I found a couple of tv tuner for the MFD2/RNS2 system (I think the same on my car looking from the photo), and on tm.techmark site I've see some photo of the navi system unmounted. so I've see that there is the AV connector on the rear side. Elsemore if I push the AUX button, then the AV/AO input, it start the black screen where i'm stopped and the screen with the alert of the protection for video image when the car is in motion so I think that my navigation system is ready for the TV system. Now I'm asking to someone that now more than me if it's true waht they told me on VW or thay want only make me paid much money for something that is very cheap.
    P.S.: I have a TV Tuner model 4D0919146B for the MFD model with the cable for the MFD2. Is this goood for my navi system
    Thanks to everyone can help me.

    Edika