Buy the best injected one you can get. Don't bother with carbs cause they're nearly as much to insure and not as quick. Mechanically near identical to a mk1 gti whatever year you buy if its injected. Injected cars are GTI (early), storm (a GTI with the later body kit, leccy windows leather seats, GTX, and late scalas (the ones without the colour coded interiors these replaced the GTX). Pretty similar to a mk1 to drive, although driving position is lower and more laid back and they are more refined probably due to sound deadening. Be warned, rear seat passengers may need their legs amputating. You should be able to get a tidy GTX with full MOT for 500-700, late scalas for a little more and storms for a little more still. Buy on condition though, specs are pretty similar between the GTX and late scalas.
They are the best because most folks don't like the look of them preferring their common as much MK2's... Have a look on Ebay as there are loads and loads and some for not very much, just check the insurance first. Carbs may be slower but mine does 40+ miles a day without any trouble.