The 020 transmissions will fit, the case is pretty much the same. But you will need to change the rest of the stuff, the bracketry and such for the mounts and linkage. The reverse light switch is also different for the newer stuff (need to get a pigtail from a newer car and connect it to yours). The axle flanges can be either 90 mm or 100 mm depending on what options you got, they seemed to use both throughout most of the production run of mk1 and mk2s so you need to measure it. And, if it's different, you need to change the axle flanges or use different axles (which are different between mk1 and mk2) that have the correct size end.