Block change and possible conversion??

Hi guys so..my bottom end has decided to let go and I'm struggling to find a replacement dx engine.i currently have a 83 gti and have read and have been told that you can put a mk3 2.0 agg bottom end on and it doesn't require much else than bolting the other bits and bobs on from the current engine and my current head..is this correct?? If this is or isn't actually the case would anyone be able to point me in the direction of what I would actually need to do to make this conversion work and what extra bits I would need to try and source and fit..thanks in advance  for any help and or advice people can give me.

Info here.  

Engine Conversions - The Mk1 Golf Owners Club