Question about my A4 2005's stereo

Hi, I'm wondering what the best option is for upgrading the sound in my 2005 A4 (B6). Right now I have the Symphony II system (I think) with the 6 CD changer. I would like to start using an iPod for my audio. I am wondering what the best course of action is between these alternatives:

• Upgrade to RNS-E (is it even possible?) and use bluetooth for audio
• Get an iPod dock and connect it to my current system (as described in this video: http://www.youtube.com/watch?v=QdmjyKwRT18)
• Both?

Also, I'm wondering what would give better sound quality right now: Upgrading my stereo or upgrading the speakers? If anyone has an opinion on the price of the different options then that would be awesome.