Hi all i have a 04 A3 with single din concert 2.

I am looking to upgrade to a concert 2+ Double din, for a number or reasons but the info im finding is confusing and conflicting. can someone confirm exactly what is required.

As far as im aware, i need a double din cage? climate control switches and the hazards/switches the concert 2+ and a wiring adaper?

is there any guides arround, i have found one for the rns-e but doesnt go into much detail about the actuall double din conversion, please advise as i would like to do this at the weekend, if i can get the parts quick enough.