If you're considering rebuilding the 8v (which I'm assuming is the one in your car), don't bother. It's not worth the cost, nor effort. 16v swaps are probably the most common MK2 engine swaps out there. When I was doing my swaps, a full longblock 2.0 16v plus 9a tranny was running for about $1000... but that was a few years ago. I believe the prices have dropped a fair bit.
If you're feeling adventurous, there's always the 2.0 8v and VR6 12v out of the MK3, a 1.6/1.9TD(i) swap from an MK3/4 or even the 1.8t from an MK4. Each one will cost more than the last, but they've all been done in the MK2 chasis.
Check out Dubberz.com and search for
JS Performance. Give Jose a call and see what he'd quote for a 16v swap, or even one of the others I mentioned. You'll be looking at $1500+ for a shop to do it, but Jose is probably one of the best VW guys in the North West.