Not easily, the later diff doesn't even bolt up to your rear subframe. I don't know, the later subframe might bolt up to your car and allow the later diff. Another long long shot is it might be possible to adapt the plate that signals the sensor for the speedo to the early diff, then you would also need to make a sensor mount. Maybe an aftermarket electronic speedo that reads off the driveshaft and use a VDO face? Sorry about the lack of help but I think you are stuck. Sounds like a nice car though.