Have asked the same kind of question in the past.
Am in the same boat as you, manual SQ625 with bigger tyres (mine are 245/75R16) - an increase of 11%. In my case the 4.8 would be great, but some members have pointed out the benefits of the 5.12 for off-roading.
At some stage I'll be chasing the gears too, maybe even the full diffs. So far I've come to the following
5.12 -> old vit (need to find which one precisely), needs to be fitted in your existing diffs
4.8 -> from a SQ625 AUTO. get the gears swapped OR swap the diffs, target a recent zook to make sure the diff is steel.
See what members had to say on my thread;
viewtopic.php?f=4&t=42902&start=60 Some argue 5.12 is overkill, some plead the opposite. Up to you to decide
