if you want to go with the ford c/l then there are 2 tyres of alarm that go with it, both work on curcits around the door locks, but these are seperate so you don't need to worry about them

the early ones had a horn that beeped when you locked them and a different box for the alarm depending on itf it was a high/low spec car

same with the 92 spec but they came with a flashing light rather than the beepy door lock to tell you it was armed

either way you don't need to worry as you will be looking for 90 spec onwards c/l motors with cable locks and the plastic anti tamper surround on them

90 spec cars also had a reversed open/close operation so that's anotehr thing to consider