Heres the truth behind the roll over story.
Roll overs in Samurais are a problem when you execute an S shaped turn on pavement at moderate speed. That means you turn one way to avoid a wreck, then over steer causes you to over correct in the opposite direction, causing the samurai to spring upwards on one set of springs while it is turning into that direction.
This is a common problem with all high center of gravity short wheelbase vehicles. It does not actually matter how wide your tires are set as far as i understand it. It is a matter of springs and momentum.
It is also possible to flip a sammy if you are going fast and suddenly start turning the wheel all the way over without regard to common sense. But you can flip anything like that.
I am not an experienced offroader, but i cant think of any reason a sammy would be more prone to tipping off road than anything else. Its all a question of keeping your weight more or less centered over your footprint.
The only ways i can think of to reduce the tendancy of a sammy to flip in highway avoidance manuvers would be to reduce spring, increase wheelbase, reduce traction, etc..... none of which sound like good ideas to me.
I am on my third sammy, and the first one with any modifications, they have all been great little trucks, more fun than an atv and you can bring your family along for the ride. I take a lot of flack from my brothers in law, who are big pick up guys, when they see my sammy towing along behind my avalanche. But i figure its a better deal than a honda rubicon, and its street legal.
The only problem i can think of that is serious is the rust issue. If you have the time and resources its better to tackle it immediately, and coat with something rust resistant. My new sammy has hercu-liner, new paint, and a painted undercarriage, but i can still see rusty spots inside the body behind the seat belts etc......
Good luck with it!!!