those are original Audi backets, very rare to find as you can't try seat in them before ordering ($4k option in AU), surprisingly very comfortable and very tight if you want them to ...No RS5 embossed on the seats? Are those out of something else and you've replaced the originals?
I do like the hard-shelled backs. Had them in my 911 and they always got comments. Easy to wipe off the kids scuffs too!
there is few more points on my to do list with this project ....Well done mate - keep the updates coming! You're going to run out of mods to do soon!
All I can say is that you must have very deep pockets!