Just bought RAM's old disks, calipers and pads from ebay
I don't need the calipers, but needed to change my disks and pads (would have cost me about £170+vat just for the pads and disks from an audi dealer/VAG parts)
Anyway, will soon have a set of S4 front calipers in good condition (RAM's old ones, having only done 10,000 miles) plus my old disks (pretty worn but still servicable after 55,000 miles) plus the old pads which still have a bit of meat on them.
I know it seems like an odd thing to sell
but I've already had three people from ebay (who were also bidding on RAM's stuff) contact me about the very same.....so I figure it must be of some use to someone, perhaps an S2 owner looking to upgrade, or perhaps even an A4 or A3 owner.
You would, of course, have to ensure they'd fit. (I was going to buy Thorney's old RS4 brake system, but apparently it wouldn't fit easily on an S4, so there are clearly differences between the various cars)
The S4's do have monster sized brakes (321mm / 12.6inch ventilated fronts with twin piston HP2 calipers) certainly much bigger than the ones on my old 2.8Q. (276mm / 12.9inch)
Although many people upgrade, I find them more than adequate for day to day driving.
Let me know if you are interested.
-Dan