Yes a MK2 020 box will fit, the MK2 16v box is exactly the same as the ones fitted to the early MK3 GTIs

If you fit an 8v box you have to fit the right flywheel (& the right pressure plate too I think?) for the engine and the right clutch for the gearbox.
Apparently 8v GTI boxes are a good mod as they allow more relaxed cruising in 5th gear too, with the rest of the gears beimg the same or very similar
