The transformation now nearly as complete as I will make it : this thread will cover the external bits, namely the S-line bumper cover with the addition of an RSQ3 grill. I knew from the day I ordered the car (July 27th) that during the order time, I'd be procuring S-line parts not yet available for the NAR yet - namely, the sports steering wheel, gearshift surround, door sill trim panels, front bumper cover and fog-light grills. I did NOT want to change rocker panels and rear bumper under-fascia just yet (and may not in the end). The biggest reason for me to do this was first function (as in the wheel and shift lever) and form (the front bumper cover and grill). I realize that these are all entirely subjective, but knowing Audi now for a few decades has provided me my own perspective and taste.
The steering wheel went on even before I picked up the car, as did the door sill covers. The e-code rear lamps went on a week or so later and now the front bumper cover and RSQ3 grill are on as shown below.
I got a used bumper cover from the UK that I found in reasonably good shape and for about 10 cents on the dollar to a new one. Shipping however was a bit stout, but in the end I was still ahead by two-thirds if even I could get one in the US (which right now you cannot). I had a friend procure the fitment bits for the bumper cover also in the UK and he was also kind enough to ship them well-packed for me.
Inspired by CortinaQ3 I took a chance on an RSQ3 grill that was not supposed to fit an S-line bumper cover, but looked (and measured) that it could. It did - mostly. The used bumper cover was prepared, repaired (in a few places) and re-finished in my new car color Tundra Brown, while the car was getting it's first few miles (161 to be exact).
During the fit-up of the grill we noticed the bottom horizontal section of the S-line vent would not fit over the RSQ3 grill, so we had to make some slight modifications - notably the bottom ridge had to be trimmed about a 1/2" along its vertical rise across the entire horizontal lip. See pics below where it's marked with a red line and pointed out with yellow arrows. The blue arrows show a couple vertical gussets that had to be trimmed back about a 1/4" to allow the bottom vent to seat fully.
Other than that, the only other item was the plastic cover for the bumper proper - the large aluminum cross member - is a bit taller in vertical profile than the EU one, so the cover for an RSQ3 will NOT work. We simply sprayed the bumper with matte black paint as shown (this was just the tack coat - there were 4 more) - which would save about $40 anyway (and works just fine).
...and here's the final outcome - a bit more aggressive fog-light grills and the RSQ3 grill - MUCH cleaner in front - and lucky for me, we don't run a front plate in SC, so no risks there -