Fwiw , I did my RA4 upgrade on a budget like so :
1rst I installed an RA2 5.0 $150 touchscreen radio ( plug n play )
2nd I installed a near new steering wheel that already had the audio controls & VR / Phone button for $150
3rd I installed a nearly new mirror with microphones I stole for $50
And then I bought the header harness for the mirror from my local dealer $28
I was happy with that for about a year , but during that year I was barging shopping for the remainder of my RA4 Upgrade items , since I had plenty of time I found great deals on the rest of the items I required for the RA4 upgrade as follows :
1) a 2013 Canadian RA4 with US maps for Navigation for $275 , this is a great radio for the price .
2) a used getupkid 7 to 7 short conversion harness from a member here for free
3) HVAC module off ebay $60
4) 911 delete plug ( didn't need it with the CA radio but I got one for the future for only $10 so why not
This is the approach I chose so I didn't have to let go of all the funds at once for the full RA4 upgrade , I kinda did 1/2 with the RA2 then the rest latter with the RA4