i've seen the superpro ones. very similar to superflex, who are also aussie. theyre a different and better design to the powerflex ones IMHO. the shock still gets relieved because there's no torsional resistance in the vertical - they act as a bearing. what they do is to reduce the lateral movement of the arm, improving the tracking through corners. Commplete PITA to fit but i found them excellent. definite improvement in tyre wear too. i got 3000 miles more out of the fronts (same replacemetn vred tyres).
i also, as smaky said, found the 145 QV incredibly sensitive to tyre pressure changes. i ran 33 front and 31 rear and it felt good at that.