Non-Torsen LSD
 

I see Giken, Cusco and Tomei. Which is the best unit and why? Or does it matter?

I'm looking at the 1.5 way models to mitigate inner rear wheel lift Torsen tail slip when driving the twisties hard while I transition from braking dive in to exit power application through the apex.

Some sites show the Tomei as discontinued. Is this product wide, or just a site no longer carrying it? Concerned about clutch pack part for wear and tear service. Or is the life long enough not to bother?

Also thinking about a 3.9 gear swap while I'm at it to make the commuter a bit lower rpm for hwy speeds. I'm supercharged or I wouldn't be entertaining that premise. And currently a 4.1 ratio stock with Torsen LSD for baseline.

Thanks for any input, I did search for a while and couldn't find answers without reading the whole library.

Best is subjective.

More important is that you get a diff that is tuned to what YOU specifically want.

I would recommend the OS Giken unit, with some modifications for your supercharger and tire choice. PM me to order, as it will be custom, not off-the-shelf.