I have just bought a B7 RS4 which has the Concert unit fitted but the previous owner also had an RNS-E unit which he never got round to fitting.

I've spent a lot of time googling and reading but wouldn't mind confirmation on a few things

I have the Audi part number for the Double DIN cage so can order this. I know I will need a wiring harness but is this the right one?? AUDI RNS-E Adapter Kit P&P QUADLOCK + Diversity Antenna Adapter FAKRA A3 A4 A6 | eBay

Once I have fitted the cage, put the centre console back together and trimmed down the climate control unit do I need a replacement trim around the ashtray/Gearstick??

Providing all the above is correct and I plug it all in, what can I expect when I first turn it on?? Will it just work?? I've read about needing VCDS to code the unit to the car. Whats the purpose of this??

Many Thanks