Jay - stock item is a viscous LSD. Aftermarket ones (CUSCO, NISMO, KaaZ, etc) are also LSDs, but they are mechanical and utilise clutch plates. I don't think anyone seriously wants to drive around with a fully locked diff...
I think 2-way LSDs will provide the most consistent reaction when the tail steps out of line as the locking action remains the same off or on throttle. 1.5-way can be a bit more snappy, as the locking action when off-throttle is half of what it was on-throttle. I run a 2-way LSD in my car for circuit / drift use. It was quieter when I had a heavy duty clutch, but bites a lot harder now and is noiser with my button clutch. Usually get confused onlookers wondering what is wrong with my car when the LSD does it thing @ parking speeds, but that's all.