Hey fellow Z-heads

I having been reading a lot of posts in this forum on how everyone made their factory Nav play dvds using a rgb convertor and a few other things from Nav-tv.com I think it is. But If anyone has done this can they tell specific what products they used and the price range if possible. Any help would be greatly appericiated. I also like the work that I say where some had a nice factory install look of a toggle switch between Nav/dvd/gaming console .