The BMW led signals are only about $50 more and they just about the easiest plug and play item you can get. Based on looking at the picture of the TT ones, the BMW led signals are just as short (horizontal) and narrower in height (vertical).
If you do go the BMW led route, make sure you order and receive the right ones, the front and back are different. The rear has longer brackets to line up with the tail light while the front has shorter brackets to sit flush with the mounting point.
Plus, you can get some M&Ms for free depending on where you buy them...
(click on lighting)