Engine wise the difference between the 8v carb & injection models is thus:
1. 1.6 Carby blocks have different crank & pistons to reduce 1.8 block cc to 1.6 (block itself is identical between carby & injection models)
2. Carby head has smaller valves and a coolant hole round the back for the inlet manifold coolant channel, and no injector holes. (1.6 & 1.8 carby heads are the same)
3. 1.8 GTI has more agressive cam
4. GTI engine has oil cooler mounted to oil filter housing
Pretty much it
