93-95 turbo as a general rule of thumb, imo.
if you want to do any kind of autocross or road racing, try to find a hardtop or sunroof instead of the t-top, but even the t-top isn't that bad.

i like the 94+ tails, but it's a popular conversion so it's not hard to find a 93 with 94+ tails on it like the kracka that posted above you for example.

check out www.mr2oc.com for really great info and pretty much the largest community of mr2 owners. there's also mr2board.com which is pretty large as well. i think a lot of the same ppl are on both.