by carmaster » Wed Oct 03, 2007 11:16 am
You have two choices.
Because of how the Head unit can be used to control the AC and what not, you may be able to replace it with a aftermarket, or you'll loss all controls. The only choice then could be to GET ALL THEM OEM NAVIGATION PARTS. This is very expensive, and you're going to have a hell of a time finding all the pieces, wiring harness, DVD unit, Antenna.
Easy way: Get a PDA + GPS unit or get a stand alone GPS unit like a TomTom. That could most likely be the best way for you.
If you want to have more information take a look on Acurazine.com, I have seen one person do it with a TL, and it was no where near being easy.