i have the pg lsd in my z now [r-200, 3.9]. just put it in last week, unfortunately haven't been able to put it to the test yet...
install was pretty simple, remove diff, remove stub axles & cover. remove bolts & brackets which hold bearings/ends of "carrier/spider gears. punch out roll pin which holds [approx] 5/8" pin thru center of carrier and remove the pin. insert pg between spiders, reinstall pin. i believe they have tools which [once compressed] hold the pg together for install, i made my own. then reassemble, using ls additive in the diff lube.
i'll post more once i've logged some driving time.