I have a Titan on order and am considering adding the nav system but I can't help think that a Garmin mobile unit, I think they call it a "Street Pilot" would be better. It's a hell of a lot cheaper than the system that comes with the truck and you could take it with you on trips and use in rental cars etc. Has anybody used both and can provide some thoughts on this. I think the nav package is $2200? Thanks.