Just bought my '92

[Ryoga]

From what I've read so far my car seems to be in decent shape, aside from bad valve seals. It has 93k and a 4sp Manual. I haven't even had a chance to take a good look under the hood... just enough to make sure i wasn't buying a junker... So... I have some questions:

MAP or MAF?

How hard is a 5Sp swap, and would it benefit my fuel economy at all? Which tranny is stronger?

How much power can the stock tranny handle?

I have no interest in doing engine swaps. I would prefer to not mess with the bottom end if that's possible... What kind of power can the stock 3E-E handle? How much boost? What about with a thicker copper head gasket? And along those lines, what size turbo(I prefer Garret if possible... easier to find)?

Thanks for any/all advice!