gemini diffs can be surprisingly strong actually.
there are a number of cars that run 10sec 1/4s witha standard diff.
a mate of mine had a turbo 5l v8 in his TE that put out 300kw with a stock diff.
the thing just wouldnt break.
for a corolla though, it would be easier to just put in a T series diff or cut down a hilux diff etc