Quaife make good diffs (though how torsen diffs work is even more mysterious than a standard one 🙂) .... had one on my racecar ... due to space it was the model used for a standard classic mini ... however I put 200 horse through it and abused it on the track for years and it never missed a beat ..... . Do you know the model number? If the diff on my 4/4 ever went I'd probably go for one as a replacement.

K