Note: using weight wisely is probably a better approach.......
The power to weight issues are one of the zookies best attributes (when compared to other 4wd's). Obviously there are area's where you can skimp, and similarly, areas where you shouldn't, so using your ideas constructively can lead to notable differences.
But, in the bigger picture, there are some 'less' understood principles.
For example.............
1. We know that appropriate gearing will make or break a vehicles '4wd' ability.
2. Vehicle dynamics & stability.......which leads me to.....
3. Centre of Gravity
The centre of gravity is a simple concept (although complex in it's relationship affects) which affects everything about a vehicle, and is a generally treated with little consideration by the 'regular' auto user.
From towing, to acceleration, to braking, even simple things like packing stuff in places can make a notable difference.
In an effort to stop rambling, a simple example.
Big Steve
More to the point some simple difference between his old, and his 'new' rigs.
whilst not really much of a weight difference (i think you would be supprised as the the simple realities...) the extra mass of the h/top, and more to the point, the fact that the 'extra' mass is up high, affected the position of the coG significantly.
Similary, I think it would be quite notable if you 'added' weight down low (ie big heavy tyres, Hilux or similar diffs etc) to Steves current setup.
Sure there is a 'unsprung weight' issue, but considering that most 4wd (rocks and climbing, as opposed to touring) is low speed, this kinda negates this issue.
Remember the thread about 'height vs width' etc think about it for a bit and you might see what I mean...
One last thing to consider before I turn the computer off for the day, bare with me if you can, imagine Redzook and his progression to the Zook diffs etc etc.
His gearing is great, and probably reduces the issues of 'extra weight', his stability (cross-slope) is greatly improved by the extra width of the diffs, as well as the extra weight down low........
Imagine, how good he would 'have it', if he could reduce a bit of that mass up high........(eg, make it a soft top as opposed to the h/top, loose all the heavy glass, and 'trim' some of that plumbers rack.........

)
That would make for a tough and stable zook.
Appoligies for the wramble.