I just spoke with my BMW dealership (Moritz BMW, Arlington TX) parts dept. I just asked to price out a nav system. They quickly replied, that Moritz BMW do not retrofit BMW's that did not come with a factory nav. I asked them Y, they said it will void the warranty. I get the impression

that they didn't want to do it or they didn't know how.
Have any of you guyz heard of such a thing? Also does it void the warranty if I retrofit a nav system.