diff is a funny topic

In theory, any size diff will cope with any size motor if you are smart with it. In reality you cant always be that gentle.

Diffs break mainly due to the shock loads that they sustain during hard use. If you drop the clutch suddenly, even a new diff has an amount of play in it, and the shock placed on the diff, if repeated enough will break it.
ure bigger diffs are stronger, but if you dont plan on doing drags and burnouts, then the standard would be fine. If you are a keen one for that stuff, then maybe a bigger diff would be useful, but even then I would wait till the diff is buggered or it breaks (not ideal thou to wait for a tow after a drag!)

The big question really is.....
what do you plan to subject the diff to?
Get that answer and then you can decide. Im not sure what is an easy swap, others can help you in that area.