Best aftermarket audio system for a new Toyota Matrix

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> JBL AM/FM 6-Disc In-Dash CD Changer w/7 Speakers (EJ)[/color]
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> AM/FM 6-disc In-Dash CD Changer w/6 Speakers (EV)[/color]


If I was to get NEITHER of the above audio systems and therefore have the
regular standard audio unit only, what would be some recommended audio
systems I should consider installing aftermarket? (Money is not too much of
an object, but I'm not into volume in audio - quality of sound is much more
important than volume. I don't turn up the volume that high.) Different
features/flexibility might be more important, for example, being able to
easily play MP3s or hook into another digital/satellite audio network, etc.,
plus good reception both AM and FM.

Bud H