I'd ignore any information on the 2010-2012 navigation system. The 10-12 system is DVD-based while the 2013 system is hard-drive based. That alone is a significant difference, and if I recall correctly, the interface has been revamped for 2013. Those two things alone make it superior to the 10-12 models (which really do kinda suck considering how much it costs).
In fact, I'd love to know the size of the navigation unit for 2013 and if the wiring would be compatible for the other 5th gens.