I think you mean (Audi) 'TT' is a hairdresser's car...

(VW) Golf TDI vs (Audi) A3 TDI... both are TDI...

The thing that sucks about a lot of the Audi choices (in the US) is that you have to buy the big NA motor to get AWD, and then they force-feed you DSG. If you get a 2.0T, you can get a manual 6spd, but you're stuck with FWD.

Golf TDI isn't a bad car at all, can be had with a 6spd manual, and while the motor doesn't have a lot of HP (140?), it has gobs of torque (236 ft/lb), and great gas mileage.

Or you can get an A3 if you prefer a 4dr wagon'ish thing, but functionally there's not much difference vs the Golf, and Audi and VW are just siblings from the same company.