You would need the later car's removable transaxle mount, plus adding the rivnuts into the car's body to mount it.
You also need to move the fuel tank strap mounting points from your late car over to the early car. Use a template for positioning them.
The other thing I am aware of is that the fuel lines are located in different places, so you will need some hoses to adjust for that.
There was a good thread on the 924board.org forum on this, but the pictures may have gone away with the whole Photobucket fiasco.