Drop Balance Motorsport a line. I’ve used them in the past and they are very helpful / knowledgeable
You need 356mm or something like that don’t you?
Just changed the front and rear discs & pads on my 2015 facelift 272 s-line as the OP - I couldn't wait to get rid of the dust producing items that it came with. The front pads turned out to be Brembo OE and the rears were Bosch aftermarket.
On my previous B8 A4 I had EBC red stuff pads all round and EBC USR slotted discs.
I recommend the red stuff pads as they are ceramic, low dust, wear well (including disc) and perform well in my opinion, even on the heavier A6.
The USR discs however I feel are overpriced and whilst looked good I suspect a little unnecessary (and slightly louder).
I wanted to avoid an aftermarket look on the A6 so went with Zimmermann discs - they are an original equipment manufacturer, so as good as genuine at nearly half the cost, although I did have to wait as they came from Germany. The Zimmermann discs have a "Z-Coating" to delay rust too - so far so good, but its early days.
I'd recommend this set up for Original Equipment quality and look, improved durability at reduced cost.
Part numbers and sizes for the OPs 272 with 4 pot Brembo calipers:
EBC Redstuff Front Pads - DP32168C (£66 Ebay)
Zimmermann Frt Discs (345 x 30mm, Codes 1LP & 1LJ) - 100.3356.20 (£114 AutoDoc)
EBC Redstuff Rear Pads - DP32082C (£68 Ebay)
Zimmermann Rr Discs (330 x 30mm, Codes 2EA, 2EE & 2EJ) - 100.3358.20 £92 Autodoc)
The BiTDI runs 356 disc that are also wider on the front, but I believe the rears are the same.
Hope that's some help,