Feal 441 "Balanced" coilovers.
Bought this setup with 7k miles on it and never got around to installing it before I sold the NC.
$800 picked up in Phoenix or you pay actual shipping. The box is neither small nor light, however.
Manufacturer's URL:
https://fealsuspensionstore.com/feal-coilovers-05-15-mazda-miata-nc/
Photo of actual parts: