I just purchased a 2002 RX300 with the Nav system. It has never been updated since the car was new. I have used a Garmin 2720GPS Streetpilot with my other car and it will route me anywhere in the US. The software version in the Lexus will only route me on major highways and major cities. Can someone tell me if the newer updated DVD software maps allow for more areas in the US to be routeable, or is that in the firmware of the unit and cannot be changed.

Thanks,

Terry