What kind of trail rig are we talking about?
Mud, Rocks, Sand, ect. What are you looking to do with it?
About, having full widths on a zuk, there was a forum a while back, and it was an 87 or 88 with fucll widths. A little to wide for me, i would just stick with the toyota axles, but if you want to run that big of a tired full widths will deffinatly do the trick.
But there were pics of the zuk with the axles im sure if you did some searches you could find it.
Amilla