on the disco 2 the ace system only has 2 hydraulic pistons. one for each axle,
the piston either pushes or pulls according to how the car is leaning, the pistons are on the drivers side (font and back), the other sides are connected to the pistons as a normal anti roll bars.
there are 2 or 3 (accelerometers) sensors dotted about the car telling the ace when the body is rolling, the axle is then pushed (or pulled) to oppose the roll.
cheers.