Couldn't find anything on the search, so I assume only gear ratios are different?

While on the subject, can someone explain what's going on here:
http://rx7cz.net/photos/workshop56/

It says FD torsen lsd, and I'm guessing they are swapping into another carrier. What puzzles me is that the unit being replaced is an open diff, and that means it's either an na fc pumpkin, or some weird tII fc or fd pumpkin that came w/an open diff and i've never heard of...

Could this just be a miata helical into na fc and someone made a mistake in titling? Is it possible to stick the fd torsen into the na pumpkin? What's going on?

Thanks ahead of time.

 

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