Hello and welcome. Spare parts are plentiful for both aircooled and watercooled Bis versions. The aircooled versions are good and you can go bananas on upgrades etc., funds permitting. The Bis version (I better be careful - not wanting to start a war) in my view has a lot of design and mechanical improvements to the aircooled like a better alternator, clutch, synchromesh transmission, lighting is better (in built relay system), heating, hatchback layout, electronic washwipe, 13 inch tires (so ride is better), relatively quieter and faster, just to name a few. That said, the Bis is not without its problems.