The head unit in the car was the original 2009 Audi unit that quite honestly was out of date in 2009…
Removal tools inserted into the corner and the entire assembly pulls straight out.
The patch cable supplied with the kit, I used the Incartec one which plugs into the main plug on the left, the others are unsued.
Original Headunit is 3.4kg
The Kenwood 8021 AND all the wires for the kit is 2.4kg. That’s 1kg saved over the standard one.
The patch lead for the steering wheel controls was the only thing to configure.
The supplied GPS aerial is used so the headunit can save using as much of my phone data. In the UK it’s not a problem, but in Europe with 12Gig a month the data can disappear quite quickly if also streaming music.
When stuck in place the Aerial will be hidden once the A pillar trim is replaced.
Wires for GPS, Microphone and DAB aerial fed from the drivers side A pillar across the lower dash into the centre behind the headunit..
Where wires passed through holes they were protected from abrasion with a sleeve.
Rear shelf cover removd so the CD player and cage can be removed.
That’s 2.1kg.
Total so far 3.1kg saved.
Microphone has a balljoint that is trapped between the roof lining and the A pillar trim, it can still be rotated and the quality of the sound is very good from the test this evening.
Did anyone ever use this mmi adapter ? No I thought not. Thats another 0.1kg
Total so far 3.2Kg
I don’t need the AM / FM radio antenna, I’ll stream it or use DAB and if I’m ever in an area with no signal or DAB, I’ll listen to the engine instead 
Total saved 3.5kg
All the trim replaced, facia fitted and tested. It works ! The quality seems pretty good too. Levels adjusted on the inline amplifier which sets the maximum volume, the lower that is, the more sensitive each increment of volume up/down. Found the right balance where Max is certainly loud enough for me 
With Matt helping we were able to get this done in a few hours, part of which was understanding how to remove bits of trim. I went for the 8021 as I prefer physical buttons which give more screen real estate instead of ones on the screen.
I now have up to date navigation, can stream Spotify or other online music sources as well as making hands free calls. It`s not the cheapest setup but none of them are.
The bonus is we managed to save 3.5kg in the process and that’s without remoing the unused loom. Weight saving will be an ongoing part of this build and whilst it may not seem much, by the time we’ve finished I expect it all to add up to a meaningful saving.