It is much cheaper and easier to go with a used JSpec engine (approx 30,000 miles) than to rebuild. They are available on e-bay and
www.fc3s.org to name a couple places. You can put on a free flow exhaust, increase boost, reprogram the chip and add nitrous. You will be surprised at the power.
Rebuilding offers you the chance to get even more power. I have a friend (rotary mechanic) who turns 10.3 at 120 plus in the quarter (1988 turbo with full interior, stereo and AC). His engine won't last as long as a stock motor but it's great advertising!
The '89 and newer engines are slightly better than the '88 and older. Condition of the vehicle should be your deciding factor not the year.
Then there is always the option of buying one with a dead motor and putting in an American V8 but I probably shouldn't bring that up on this forum. Or you could do what I did and put the Turbo 13B in a Porsche 911. That really bothers the Porsche people.