Best NA
The early cars with the longnose crank are attractive due to their low weight, although, for pure lightness, as I understand it, the first year's car is the lightest. But I don't think any of them came with the longnose crank.
I personally like the torque and power of the 1.8L motors. I own a '94 B-package that I've had since new (and will likely keep until I am so elderly my keys are taken from me!!). I also have a '90 ex-Spec Miata that had a 1.6L. Admittedly, this motor was pretty used up, but after we swapped in a 1.8L motor and upgraded to 1.8L brakes, I was 14 seconds faster at Sebring (HPDE). That's a TON of time. Most of it was motor.
If I remember correctly, the early cars had a 4.31 rear end ratio, and the 94-97 models had 4.10. The '94 models had some extra bracing behind the rear seats, and also at the rear suspension (although I don't remember if some of this was also on the '93's, but I don't think so).
Another consideration is the wheels. The 1.6L alloys were 14x5.5, and the 1.8L were 14x6. Don't discount these wheels: the 14x6 weigh about 10 lbs, and there are 225-width tires that will fit on this wheel, although a 205 is probably optimum for street use. Later wheels with 15 or 16 inch wheels can change the effective final drive ratio (depending on tire size).
My opinion that the best overall is the '99 Sport model. These were still pretty light avoiding some of the weight gain the '00+ model years had. They also had a fairly strong motor, suspension similar to the '94-96 "R" package (slightly stiffer springs and Bilsteins), but again, if I remember correctly, had the 4.31 rear in spite of the larger motor. My son had a '99 Sport and it was quite a good autocrosser. I say this in spite of the fact that these had 15" wheels (again, my memory might be off).
The '99 Sport, IMO, has the best combination of motor, suspension and weight.