the g60 is very similar but a lot of the internal parts were beefed up to cope with the strain of forced induction, its also got much lower compression (although you could get round this with spacers or gaskets its not ideal) and the capacity is slightly lower, not that that really matters.
you'll also need the loom from the g60 as it uses a totally different ingnition
by the time you've bought the bits you'll need you'd be better off getting a whole rado and stripping it, you could sell what you don't want on ebay
have you thought about a turbo? you can use a 1.9TDI manifold after a little bit of angle grinder action and run it on g60 management - check vwvortex.com theres loads about it on there
if you've got a k-jet you could easily swap for a 16v and turbo that later for even more power - easy 400bhp
thats what im doing with my mk1
http://www.c3cars.com/VW/Turbo/
