No "M" model in '93, but they did make the black 'n' red interior '93LE. Good luck finding a Cheap Bastard deal on one of those, however.
However, since there really is no significant chassis difference between yours and a '93, why upgrade? I'm kind of in the same boat - my '99 Sport has been hit twice, has a few more rattles than the average higher mileage '99, and doesn't ride quite as nicely. On the flip side even though I own it outright I'd have to spend more than I'd get for it to "upgrade" to a clean, lower-mileage, undamaged '99. I'd then also have to transfer all of the parts I've accumulated (like the rollbar), and mine isn't nearly as modified as yours. What I'd end up with would be a mildly more comfortable and quieter Miata that didn't actually go any faster which cost me a whole lot more money. Doesn't seem worth it to me.