The nav is actually a Lexus OEM from 2002 ES model. It takes up where the current display / audio controls are. Believe me, you will love it.
It doesnt have RCA inputs, but I have seen some Lexus 2002 IPOD/MP3 kits that would work on this too. The harness would plug in directly to the CD changer.
I am trying to understand everything so I can complete this in 2 weeks. Let me know if you are interested and we can buy together, get a bit more discount. It is costing about $1600.