It's mainly for lowered cars, I think. It moves the roll centre back to where it should be because the angles of the steering arms change. It's obviously a lot more than that though.
This is a really complex bit of geometry, but essentially it affects the point in which the car begins to body roll - this should bring the roll centre back in line with the centre of gravity and reduce body roll.
I'd suggest doing some reading up, as I'll no doubt confuse matters - but essentially it's a good thing and Whiteline will have done their homework properly... hense the delay no doubt.