Good catch Meister!
On the passat you need to determine if you have an O2J or O2A output shaft set up. How this is done is pretty easy. Look at the differential output shaft on the passenger side, if you see a green seal holder between the half shaft and the tranny case you have the O2J and that is the Differential you need to order. If there is not a green seal holder pressed into the case then you have an O2A differential with the pressed in half shafts.
Installing a differential is not for the faint of heart either. I have it down to around 3 hours but then again I have all the dial indicators, runout gages and every possible shim YES you need to reshim the new bearings and adjust for proper preload!!!
Also you had better have a heavy duty press because your gonna need it...
DB