Just so you know what sort of age to look for fielder:
8v was k-jetronic up until 1988 then changed to digifant. They basically changed over during the the E'reg year so you could buy an E'reg 8v with either injection system. They are easy to tell apart however as the golf was given a bit of a facelift that year. The easiest thing to look for is the quarter light glass in the front windows, the earlier models have a triangular piece of glass in the front windows that doesn't open. On the later models the whole front glass opens.
16v was always k-jetronic for the life of the mk2 then went to digifant on the mk3.
As somebody has already said the k-jetronic system was designed with performance in mind (probably coz it's such an old system) whereas the digifant system was designed with economy, emissions and reliability in mind.
If you do go for a digifant model there are more tuning options i.e. chipping, induction kits etc and you always have the options of dropping in the 16v lump from the mk3 as it uses the same injection system. If you think you are ever likely to want to do this however make sure you get a late model mk2 as they have the same wiring loom etc as the mk3.
Hope this helps
Toby
