Hi guys sorry if this has been covered before but i cant find a thread with a simple answer.

I was hoping this would be simple but it seems far more complicated from what i have found.

Im looking to change my symphony 2 (6cd changer) to the pioneer App radio

So my questions are.

1) Is this conversion simple? I'm no stranger to changing head units but have never changed one in an Audi

2) I've heard if you change the unit the rear speakers / sub do not work even with the ISO Adapter, is this true? if so can you / how do you get around this issue?

3) I'm pretty sure i need a facia adaptor and canbus ISO Adapter is there anything else i need?

thanks for any help.