Leon,
There should be only two main types for the pre CS hatch models:
They changed in 87:
Early type went to chassis H1007931/H8000099 these had an extended length of 670mm
Later type fr chassis H1007932/H8000100>
These had an extended length of 700mm
The ones with spolier had a higher NM pressure of around 400-470,with out spoiler were running around 320-350NM..
Sounds like you need a 670mm with 400+NM
Hope this helps some
G.