Sorry to revive an old thread, but I'm from the UK and have just found this and installed on my UK 2002 IS200.
As far as the navigation is concerned it works perfectly, but on mine it won't do anything for the audio (simply says "audio commands are not available using voice")
Did any of you have to do anything differently to control the audio, or did it all just work as soon as you plugged it in?
Thanks in advance for any help