Lexus: RX330 Replacement Stereo?

Hi - I'm looking into buying an RX330 but would like to install a
Kenwood head unit into it so I can get Sirius Satellite and Kenwood
Music Keg. Since the RX330 comes with the nav system, is it possible
for me to have a non-stock stereo installed and still use the nav
functionality.....or should I be looking at another car??

Thanks