Im pretty sure, because the audi is an inline engine its slightly diffrent, i really dont know to be honnest but i do know the MK4 golf non PD 110bhp engine will fit into your car, also the 115, 130 and 150 bhp PD engines will, its relativly big job but not to hard to do.
Mabey if the mountings on the audi are the same it would fit... From what i remember of the A4 TDI engine i worked on, it was very diffrent to a MK3 engine layout. It depends what your goal actually is, if you are after power, PD is the way to go, if you are just looking to replace a turbo and mabey a quick upgrade at the same time, i would stick to your hunt for a 110 turbo. Mabey if you have the choice of a 110 engine that fits and fancy a project, it could be a good option as the later engines especialy are alot smoother and quieter as well as faster.