Depends what you need the cars for? Commute? weekend toy?
Without knowing any details I'd say keep the Mk2 after seeing the work you've put into it 
Well that's a valid point, I'll be using it to do about 1200 miles a month commuting to college and back (which the mk2 is currently doing), plus trundling around. I would like to do track days but as yet still haven't managed to get to one yet.
I am also starting my own business in next year or so doing paint and resto custom work but my old boy has a Transit van that I can borrow if I ask nicely...
Fancy a change, but I know I'd miss the screaming 16v, but then price of petrol and there aren't too many caddies kicking about my way.....Just being an indecisive bugger really. But kinda good decision to have to make.
mk2.... wait caddy diesel. ooow too hard of a decision.
both?
Outside rules can only afford to keep/insure one.
Sell both and get a 8v golf3... no brainer 
if it's an 8v TDi estate that'd fall under "something else"
Poll