jgains: thanks for the response, I'm experienced with aftermarket audio, i've got a mild system in my supra, however, it doesn't have navigation, so i'm kind of leary about messing with that whole thing. I am aware that the quality will be much, much better, but i just don't know if i'll really care . . . you get me? I mean I'm into it, but i think i'd be happy without doing a head unit change. Anyway, I can always just do this stuff now and change head unit later . . another day, nuther dollar.

about the steering wheel controls : i just read a post about somebody who used this module to make them work with an aftermarket head unit, check it out

about the nav voice : if you miss that chick's voice tellin you how it is . . . you can try routing the nav's sound to a dedicated speaker, something tha's amplified that you can hide somewhere in the cabin and that will be dedicated for the navigation's voice - control the volume direct from nav settings. I know that's what people do in the benz and toyota world, check into those options . . .

PLUS !!!! what if something goes wrong with the nav . . ? warranty, etc. etc. i'm just talking out loud, don't mind me /