First off,
Thank you for weeding through
all the endless listings of
Cheezy XBO LLDs
( Limited Life Diffs ) (it's called listings polution)
To look at my Genuine JDM LSDs.   Just in from Japan
(where Real JDM LSDs come from)  

An Early Mazda Miata OEM Viscous LSD For the Pre-'94 roadsters.

Includes the special shafts required for the Viscous LSD to work.
(note second spline on one shaft) 

I ship anywhere in the continental US
for $26 ( includes insurrance )