I agree with your comments about the sound system. We just turned in a SAAB 9-5 at the end of it's lease (amazing audio) so the audio transition to the stock Lexus 330 system was particularly painful. I would like to upgrade my system as well, although I might actually be tempted to buy the Navigation Package in order to get the Mark Levinson system, if in fact there is actually an option to upgrade with a dealership installation. Failing that, if you get any reliable information on less costly upgrade alternatives, I would be greatful if you could pass it along.