hello bro..
dis my opinion study on dis parts.. basically, we must know the function on dis part.. strut bar, fender bar or any bar is applied to hold the absober, body and arm.. for proton, the absober mounted on the body and indirectly the bar would avoid the body from move or twist.. so the handling would become perfect..
the point is, the better bar is from the stiff material but not the light material.. steel is heavy but stiff than aluminium.. CUSCO become expensive is not only bcoz of brand but the material is already expensive.. but aluminium does not rusty.. then hollow bar is better than solid bar.. solid bar become better if have some shape from xtrusion or forged process..
plz correct if i'm mistakes.. thks..