Navigation Upgrade

[RXster]

I have been reading for hours now and I really havent found a solid answer on the ability or lack thereof to upgrade from Generation 4 to generation 5. I currently have a 2004 RX330 with version 4.1 Navigation disk installed. I have seen threads were people have tried it from a different make of vehicle with no luck, but what about the same make (RX)? I would love to have the functionality of voice command and bluetooth that comes with the Gen 5 system. i asked the local dealer when i purchased the vehicle if this was possible and he didn't have an answer. He mentioned that the location for the microphone is in place just like it is on the Gen 5 systems (in the center of the roof mounted console beside the map lights). Not much help. I asked if the harness for the voice command button was already in the sterring wheel, again, he had no clue. I would really rather not pay $250-$350 for the Gen 4 6.1 disk just to upgrade the streets.

Does anyone know if there are any significant changes from v4.1 to v6.1?

Your comments are greatly appreciated,

Shane