BMW rear shocks and Fit rear springs?

[Caramanos2000]

I know it doesnt come with one. My point is this: usually sway bars attach to 2 moving points, 2 points that move independently and the bar ties them together. In the rear of the yaris all your doing is connecting a solid bar to a solid bar, the stock beam is so much stronger and larger than the sway bar, why would the sway bar make any difference? Its nice like the 2 anchor points (the shock bolts) are flexing independently and somehow that little bar is gonna stop it.