If you are familiar with the guts of a transaxle, know how to use a dial indicator, can set pre-load on bearings, and have good mechanical knowledge and ability, I don't see why not.I'm sure that the Quaife LSD would come with some form of rudimentary installation instructions to follow.
I didn't trust myself, so I had my Quaife installed, when my gearbox was rebuilt. The cost of an error on my part, was something that I couldn't live with! My wife would have killed me if I blew up the gearbox, immediately after finishing the car! /ubbthreads/images/graemlins/shocked.gif
I agree with Bill with one addition, in all of my experience with Porsche, they always require at least one "special tool" that you truly can't do the job without and they ALWAYS cost an arm and leg to buy!!! As I've not had my G50 appart yet, I don't know if you would need one or not, but you might ask around first!