Only two spots of trouble for my 2013 TT. The first week I broke the flimsy radio antenna. While removing the cover, to protect the baby, the antenna got caught, bent and snapped. $130 for a replacement!! YIKES!! I went to the local auto parts store and spent $5. on a flexible rubber antenna, works great.
Just this past week I had scheduled maintenance due and just three days prior to taking it in the battery died. Must have been one of those from the bad batch that others have posted about.
No regrets on purchasing the TT. The tires have lasted to nearly 15k miles!! Never got that kind of mileage out of a set of tires on my ST1300
Fuel economy is much better than I expected, 56 MPG but I rarely get at and above 80mph.