Alfar7, your objection is useful clearing, 75W-90 NS is excellent choice, and six discs are for theory not common use.
Richards, about spline number you are absolutely right (I have not paid attention to the photo where you could easily count them) but it is not 33/GTAm LSD (10533.17.043.E02) suitable for GTAm only with 10551.17.300.99 15 splines axles, this LSD was of different external shape. The LSD that Alberto posted is 10510.17.043.00, 15 splines unit, used on different Alfas, included GTAm.
Alberto, for LSD work you must provide special tools, few specific extractors, but that is not problem. Problem is specific tool to calculate pretension of the mainspring (in case of changing the discs obviously), and set the closure ratio. There are some alternative methods but they are not so accurate as original tool.
Here is 10533.17-043.E02 in bad photo but it is clear that the shape isdifferent