I made a cable today that allows me to connect any external audio device to my 2002 SC430. It sounds great, better than a modulator or casset adapter. XM satellite radio is really sweet now. All sound controls are still performed via the head unit (i.e, volume, base, mid, trebble...).
If anyone is interested in a plug and play adaptor that supports an exteral audio source and mute control for their Mark Levinson system, let me know.
Rocky Livingston
rlivingston@earthlink.net