Hi the symptoms of clutch failure are simply diagnosed, take the car out get it up to temp then find a nice hill to go up and change up early so the engine is beginning to labour then slam the throttle down if the clutch is knackered the revs will rise rapidly withe no extra acceleration, I am in no doubt Audi will tell you its gone just to get the job and charge you even more money than anyone else, I have driven over a million miles in cabs and stand on me thats the best way of testing the clutch, Audi ownership is for people with deep pockets, yes they are great to drive, yes they are powerful, but you know what the parts prices dont justify the ownership, I just bought new discs and pads for My Passat and they were a bargain at £123.40 compared with the A6 which was Brembo as well at £270.80 even aftermarket its a JOKE.
Steve.