Here's a good explanation (and sales pitch) for LSDs in general and the Wavetrac diff in particular:
WavetracHaving done some more (internet rabbit hole) research, I'm convinced an LSD would be beneficial to safety on a road-going Plus Six, and I'm now leaning toward the Wavetrac over the Quaife.
However I'm also convinced that
if I wanted to push on with the car, rather than drive normally, a Nitron suspension upgrade would come first.