Audi Tech's Experience
 

The following information comes from an Audi Tech and will give you an insight to the kind of problems being experienced in the workshop.

Clutch master cylinder failure-Recall affecting some TTs & A3s-Symtoms are that the clutch pedal will go to the floor and not return endless physically pulled. Cure-replacement clutch master cylinder, If fault continues after replacement, Slave cylinder & pipe will be replaced.
Window motor/control unit failure-no recall issued but warranty item-Symptoms are the widows dropping by themselves & generally not operating as should do. Cure-new window motors with integrated control units will be replaced.
Front-lower wishbone bushes (ones toward the rear of the wishbone)-common fault-Symptoms are a knocking noise from the front & visual perishing & degrading of the rubber. Cure-with wishbone removed bush can be pressed out & replaced.

Front anti roll bar inner 'D' bushes. Symptoms are a knocking noise from the front & sometimes splits in the rubber, in most cases no play can be found at bushes but if no play can be found from other suspension components then 99% of the time its the 'D' bushes. Cure-modified bushes are available form Audi parts departments, identified by hump/ridge in the back of the bush & on the metal 'C' mounting
bracket. Often found the Anti roll bar its self to be cracked where the bush mounts causing the bar to sit to one side of the car. Cure-New anti roll bar.

Rear shock absorber lower mount/bush. Symptoms are on visual inspection the rubber bush is parting from the shock absorber, haven't seen one bad enough to cause knocking but if left long enough it will happen. Cure-new shock absorbers, bushes aren't available separate.
Another thing I have noted when working on TTs  is due 2 the badly corrosive salts etc on our roads The gearbox casings on many TTs are starting to show signs of bad corrosion, looks almost like acid has been eating away at them where bolts & plugs are mounted, I suspect this will be a future TT problem!