I doubt they are much stronger, Id say they are basically the same, mine was just to replace the welded center I had...
I'm about to drop a significant amount more power in my 20, and will be running a shortened R31 diff, but that will be a bit of work.
There's a few upgrade options, like hilux, T series, or even a ke30-55 diff may do... all need a bit of work to make them fit though, really depends on budget, how much weight u want, and how keen you are to do the work