I hope this helps...
An anti-roll bar is a spring (more of which later) that connects one side of the suspension to the other. As you raise one side of the suspension, the ARB tries to raise the other side. By doing this, it effectively uses some of the energy from the weight transfer to raise the other side of the suspension, thus keeping the car flatter in the turn.
It is a spring. The energy you put in 'bends' the metal. As the metal resists the bending, it will lift the other side of the suspension. Like all springs, you can adjust its rate - the amount of effort it takes to compress the spring - and that affects how it deals with apportioning the weight transfer across the car. Strictly speaking, an ARB should twist in the centre section (hence the term torsion bar) but in practice the arms also bend, especially in our model cars. The centre part of the arm (connected to the chassis) is connecting two levers, and the ends of the levers are attached to the suspension at the leverage points.
To make an ARB stiffer you can either increase diameter of the bar (I am ignoring 'blade' type ARBs as they aren't used on electric cars, only gas cars) or change the position of the arm acting on the lever. In other words, make the bar thicker, or move the leverage points on the lever up or down.
If you move the leverage point closer to the centre section, you will stiffen the arm which increases the stiffness of the ARB. Moving the leverage point further away has the opposite effect. For all practical purposes, doesn't matter how far apart the pivot points are on the ARB (where they are attached to the chassis) to determine stiffness, but it does matter how far the leverage points are from where the ARB is attached to the chassis.
ARBs are springs. Worse yet, they are undamped springs. For any given energy input, the ARB will give an immediate energy output. There is nothing to control the rate at which the energy is released - it has no damper. That's a bad thing because at the extreme, it will make the car rock across the chassis (from one corner to the other) as anyone who watched Andy Rouse in a Cosworth 500 Touring Car will remember! So, there comes a point where the ARB will interfere with the damping of the suspension, and control of the wheel travel is compromised.
ARBs will also have a role in limiting suspension travel (they're rarely seen on long-travel rally cars, often seen on short travel track cars) and will add weight and complexity.
Although they limit chassis roll, they do this by taking the weight transfer, unloading the inside tyre, and loading the outside tyre. This reduces grip at that end of the car. Also, because they react to one wheel moving up/down, and are connected to the other wheel, they will transfer any motion over bumps from one side to the other, causing the chassis to wobble from side to side over bumpy terrain.
