Originally Posted by VABAM

Going from non-nav to nav is not impossible but it is very impractical and going to cost a lot of money. The cars complete stereo wiring harness needs to be swapped out. I'm not talking about one or two connectors in the dash I mean the whole wiring harness that runs through out the whole car. This is due to the subsystems that need to be added like the GPS antenna, ECU inputs into the NAV system, and a few more. Also all eBay sales of the factory nav system that I have seen do not include the GPS antenna. The GPS antenna is not the antenna that is on the roof, it is actually in the dash above the HVAC fan/ glove box. Depending on what which system are starting with you might need a new steering wheel so you can have useable steering wheel controls.