Q.
Due to the stock miata torsen diff housings having a notch made into the passenger side by the factory to allow it to break in a collision, there are several weld in braces available that essentially make it a solid piece.
The FC RX7 diff housing is the exact same dimensions but do not have that notch. They use the same bushings as the miata, house the miata torsen without any modifications, and allows the diff to bolt to the factory PPF exactly the same.
Because of all of this, can I use the FC RX7 diff housing which I know to be strong and safe rather than weld in a plate on the miata housing to avoid any risk of failure without taking any points? The factory diff will still be used and will not be swapped for any other diff.

A>
No. the rx7 diff housing cannot be used unless claimed for points.
A diff has points assigned, and if non stock is used, points must be added for everyone that chooses to do so.
You can weld the notches 0 point add or Use additional material for material points. Nothing is free unless it's on the free list

Verified 7-2-24 by TECH