Alternative Aux Input

[vinuneuro]

I've been wanting to do aux input on our 2001 w/ nav+dsp for a while now, but it seems cost prohibitive to get a new radio module just for this. I'm considering an option like this:

http://www.enfig.com/cgi-local/SoftC...b97+1141640240

However:

1. I need to buy an Alpine Changer for this set-up right?
-Will the sound quality be as good as it is now?

2. Will I need to buy the cable going from the changer to the blitzsafe module?

3. What is that round connector in the bottom right corner of the picture?

4. Are there any downsides to this set-up?

5. If I get an alpine mp3 changer, will it display the text on the screen?

6. Will an Alpine changer mount ok in the factory location?

TIA