Just curious what the most affordable way to accomplish this would be. Is it possible to replace the non-Nav with the stock Nav? Is it a simple one-to-one replacement? What's the price of the stock Nav unit? Are their any after-market head-units that would be essentially be plug-n-play? I'm pretty comfortable with removing/replacing the head-unit, but when it gets into the wire diagrams I start to get a bit lost. What's the best way to do this? Any advise would be much appreciated.