My friend asked a shop to attach a DVD system to his Navi on his E55 AMG and they said that it would affect (negatively) the Drive-By-Wire system.. just wondering if the same could happen to the G35c w/ stock navi.

 

First I would have to ask how it affects the E55 Drive-by-wire? But to answer your question, many have hooked up several different types of Video sources to the stock navi screen with no ill effects on any system that affects how the car runs.