Stock S4 brakes info please

[SonTon2003]

I searched and didn't find the answer so here I go...

How many pistons front and back are on a stock 2001.5 S4 brakes, thanks.

 

[simon_golf_tt]

S4 fronts are twin piston sliding calipers and use 4 pads (both pistons on one side). Rears are single piston sliding calipers. The rears changed from solid disks to vented ones around about 2000 - not sure of exact date (still single piston though).