My 1993 has 160k and a few issues, so I'm thinging of replacing the engine and trans with new. I could go with stock, but I was wondering if I have any choices. Might I be able to get a little more power with a different drive train? Which ones will fit this car without major mods?

you can put in the mazda block from a GT and a few other Mazdas that came with a turbo. Best thing to do is try talking to the Ford boys at the shop. It wont cost you to talk and chances are they have done it. They may be able to tell you everything you need to know.
If you dont want to pick up a Haynes Manual, step by step and well worth it for future repairs.

The easyest swap would be a 2.0 from a 97 Escort.