Uh, hate to tell you this, but the TDIs actually have a unique gearing compared to the gassers. The commercial 6th gear add-ons DO NOT work unless they are specifically for the TDI. You may even end up with a slightly shorter 6th than your current 5th (you want taller...not shorter). The only way to do a 6 speed conversion is the european gearbox right now. There was a company which had a kit for the A3s since there was no 6 speed option...but they have stopped making the kit. It was a european company, and apparently people who want the 6 speed in their A3s there, just go to a junkyard and pick up a 6 speed tranny for less than the gear upgrade.