BMW Aux Input Quality

[sccxvely]

So i have a Video Ipod 30gb and i was looking forward to installing the BMW Ipod connection but the dealer informed me since i have NAV and a CD changer that wasn't possible (i have no idea why) but they did say i could install the Aux Input and use my Ipod but when i asked about the quality of the sound dudes response was "honestly i have no idea" So my question, is the quality of sound from the Aux Input as good as the quality of sound from the BMW Ipod connection?

But since my cd changer is a MP3 player, who needs an Ipod connection correct? I currently use 2 cds with about 200 songs on each, so much for a 6 cd changer lol