Rear rotate refers to cutting the spring cups off the axle, flipping the upper link mount 180 deg. (to tilt the top of the axle backwards, "rotating" it), modifying the rear lower shock mounts, and welding the spring cups back in the new rotated position of the axle tube (otherwise the springs would have a sharp curve in them, causing premature wear).
What you gain: pushes rear axle back, increasing wheelbase and departure angle, improved driveline angle, and can allow for larger tire/less rubbing.
How-to in the archive! At the following link:
http://www.zukiworld.com/month_100102/feature_hagans_rearrotate.htmWhile I'm on topic, widening the front involves adding caster angle by relocating the rear bolt of the control arms 1" outwards on each side. Widens the front track, pushes the balljoint forward...but puts more leverage on the front coils and MAY cause premature spring wear, and also could put them in a different position (they won't be vertical anymore, but tilted forward at the bottom)
What you gain: pushes front wheels forward, increasing wheelbase and approach angle, and can allow for larger tire/less rubbing.
How-to in the archive! At the following link:
http://www.zukiworld.com/month_120102/feature_hagan_frontendmod.htmThis link also details the front axle mod to run two driver's side axles. I think since it is wider, the passenger side axle MAY pull out when the wheel is turned all the way to the right.
And I'm just helping someone out because these articles were helpful to me when I was first researching lifts and mods.

These two articles are saved in my internet favorites.
(The only reason why I didn't do them is because the 30" tire is all I need to run...for now...but I also figured that the guys at Calmini designed it a certain way for a certain reason and I should leave it alone. Plus, I want the springs to last a long time, and "supposedly" these mods cause the springs to wear faster.
Don't take my word for it, ask the guys who have done it, maybe they can tell you. T
he general consensus I read is that OME springs and struts are more durable than Calmini's and they ride smoother too.
But, in Calmini's defense, I also heard that they are making the springs differently now. So maybe they are different from the "old" style.
Again, I can't back this up with evidence but it might point you in the right direction or get someone else to respond).