2003 nissan 350z

want to install pioneer 6500dvd system. I have navigation system in car already and is tied into the factory system. Best buy told me it can not be done. any suggestions? also changing door speakers and adding amps and subs.

Not to slam Best Buy or any Big Box stores but you should only use them for drop in stuff for older cars and decent deals on some of the name brands. I just got through adding a video source to a 350Z and an Infiniti G35 (same car different name higher price). The company that sells the piece is called Nav Tv, here is a link http://www.nav-tv.com/products-dealer-universal.htm, not sure if they will sell to an individual or not, but basically on those cars you have to cut the RGB wires and the sync wires (2 of them in those cars) and tie it into one of their convertor boxes with a switch. It is a very cool thing to have although you have to do your audio input with an FM modulator if you are leaving everything else stock.My mechanic told me, "I couldn't fix your brakes, so I made your horn louder"