That AVN 5495 is going to be awesome. They fixed the low preouts from .8 volts to 5 volts(doesn't really matter if you're keeping the stock speakers, but means alot if you are adding amps)
The Eclipse Navi units are the closest you are going to get to factory nav. They are the ones who make the factory Navi(fujitsu-ten)
IMO it's alot better than the factory navigation because you are also getting a way better headunit for sound quality and system adjustability. You're also getting a 20GB Hard drive that records the songs you play from the CD to it's internal harddrive. It also records xm and radio broadcasts, has a memory stick slot for even more mp3 files.
I strongly suggest the AVN5495
