Some assembly required. :)

Stock on the left and the quaife on the right.

If you have to do the differential, it is easy enough to do the clutch at the same time.

A phantom grip is what they call a locker differential. It is an old muscle car trick carried over. I still do not like the idea of friction from metal on metal and it does not address the weakness of the stock differential.

The quaife is ATB (automatic Torque biasing) and is essentially gears and very strong.

You will also hear about clutch types (KAAZ) which allows you to preset the load change yet wears out like any clutch will (yet I have never actually heard of someone having to rebuild their diff from a worn out clutch) and viscous coupling which uses a fluid to transfer torque and comes in a GSX.

I am happy with the Quaife.