Did a quick search but did not find a direct answer:

I have done an NA miata cage, but am needing to start a cage in my NB. Will a pre bent NA cage work in an NB? Jeg's has some decent looking NA kits and is local so no shipping$ but no listings for an NB.

If there were just a few modifications to fit the NA kit to an NB I would be way ahead. The roll bars are the same if I remember correctly, hoping not a width issue at the front.

Thank You

 

you can fairly easily swap NA and NB interiors, and the rear halves of most cages are the same for NA/NB

So it should fit ok.


Main things I can think may be a concern:

Glass window soft top may not work, depending on rear diagonals.
cage may hit dashboard or door cards.

But since you're looking at a cage, i'm assuming it's not a street car, so you'll likely just cut the dash to fit, and bin teh door cards anyway.

 

The miatacage.com piece works across NA & NB, all years

 

Cage fitment for fully-stripped NA/NB is nearly identical, aside from small details like footwell intrusion bar. That said, the kits off Jegs will leave little room for mounting a seat compared to a kit with a main hoop landing on the package shelf or a custom cage that eats some of the seatbelt tower space.

TLDR: those kits will work equally not-so-well in NAs and NBs.

 

It's basically the same chassis (for caging purposes).