cant speak for the gt diesel versions as im unsure, but the early 1800cc 20v gtis came with standard golf suspension, and 15" wheels with 65 series tyres, this could be upgraded at the factory to the same set up (26mm lower, the golf 1.8 't') suspension set up, same dampers etc just slightly shorter springs, the 15" wheels could also be upgraded but im not sure what to? wether it was a different style of 15"s or 16"'s)
either way, if you are considering lowering a non turbo gti, always choose the springs for the 1.8 t model, because it is lower than the standard setup of the non turbo you will get (for example, 40mm drop springs) you will get about a 66mm drop in height which is good and will rid you of 'oil rig' status!!
