A set of extractors would be a cheap first bet, but as old corollas says, it depends how much you want to spend. Dropping in a 2TG is a pretty easy task and gives you a great top end, or just welding the diff makes it much more fun off road.
I have driven a bunch of 3Ts and am amazed at the difference between stock engines. Some go pretty well, others are totally gutless. Maybe yours is particularly gutless cos it is old and flogged.