rear ARB's on a VAG beam work, big time.
The rear beam design is a purposefully flexible V shape to allow a degee of indenendance between the two sides.
Adding the ARB joining the two sides, and clamping it rigidly to the beam resists this flex and reduced roll.
As Adam said though, despite the change in feel, it isn't always actually better, but the balance and driving feel will certainly be altered