NA and NB Miata seats are a direct swap. All 1990 to 2005 seats are bolt-in.

The ideal dimensions for any Miata seat is a 19.5-inches base width and a 21-inches shoulder width. Perfect shoulder width depends on the height where the seat widens. You can usually get away with a maximum base length of 24 inches, a maximum base width of 22 inches, and a maximum shoulder width of 24 inches.