I upgraded the Brakes on my car and these are the original 320mm Discs, pads, calipers and carriers.
The Calipers and carriers have done 75K miles, the discs and pads are Genuine Audi (Pagid) and have done less than 2K miles. There is no lip on the disc and the pads are about 1.5mm less than a new set.
I am fairly sure these would upgrade the smaller brake disc size use on the A4 /A5 314mm x 25.
These calipers are the same as used on the S4 / S5 so if caliper carriers were sourced you could upgrade again.
These are £175 collected from Cannock or £200 delivered, They are very heavy.