to do it you would be swapping basically everything from a car with a 1.8, motor, tranny, wiring harness, ECU, Cluster?.
Most people dont do it because it is easier just to buy a car with a 1.8
Of course it makes perfect sense if you want a 4 door hatchback or a wagon with a 1.8.
I did it in a 92 wagon, so it is not impossible.
It's best to have a whole parts car so you can do a disk brake conversion at the same time, and you may as well get the bigger rear sway bar from a GT. If you are doing it to a hatchback then you can also pick up the GT ground effects.
SPI swap is quite a bit easier to do though