Don't even think about this level of modding with an alloy diff. Won't last 10mins in decent bush. Stocker your danger now is obviously lack of diff oil, but also crown wheel teeth grinding away on the twisted case when it torques up. Only going to make the repair more expensive.
Buggy Man you're suspension list looks good, but the devil's in the detail. Steve's right in that 33s have been put on a Vit without lift, but it didn't have much in the way of guards left:

Gearing and strengthening driveline is absolutely non-negotiable for anything over 31s IMO. It's a list I'm starting to work my way through, but there are few shortcuts unfortunately. Hilux CVs are about the easiest step after steel diff. I don't know of any options for rear axles other than the Calmini HD ones, which are holding up OK for me so far, but haven't really been tested much. I'm interested to hear what the next weak point is - if it's drive shaft unis that's OK, but if it's gears in diff/box/transfer stripping out I think I'd rather have CVs as a fuse.
CV kit any closer FatZook?