The German automaker, VW has been producing the Audi TT series for two generations. The TT shares the same Group A Platform as Audi's A4 so the powertrain and suspension are similar on both models. As a result, these two Audi models can have similar problems to each other.
One problem that Audi TT owners have experience is perhaps not unique to TTs or even Audis. The squeaking noises emitted by brakes is a common problem for car owners. For Audi owners, in particular, this problem seems to occur as the weather turns colder. In some instances this problem with squeaky brakes has been remedied by having the brake pads "roughened up." A more abrasive surface on the pad seems to do the trick. In other cases an anti-squeal compound will work.
If neither the compound or an adjustment to the brake pads fixes the squeaking or squealing of the brakes, replacement pads may be necessary. Audi may even offer a replacement pad of the existing OEM pads. Whatever the cause, this noise can be quite annoying and should be looked into.
If you are the owner of an Audi TT, consider taking your car into a trained German import technician. A mechanic will be able to determine if replacement pads are in order, or if there may be some other way to solve the issue. If the problem is simply a matter of installing new brake pads, this should be a relatively easy thing to accomplish and not too expensive.
Search for a local, independent Audi repair shop with Audi mechanics that have dealer-level expertise at a fraction of the expense.