if it doesnt make noise while sitting still. it is most likely the IWE. What you have replaced is usually not the issues. the IWE actuators are the part that fail, and the hose. take the suspension apart and inspect / get a hand vacuum and see if it holds pressure.
Nothing wrong with OE type arms. With corrosive harsh weather arms such as SVC have to covers that seal the top. All aftermarket performance heim/ uniball / poly bushing arms require more/ constand maintenance like lubing the joints to keep them operating smooth and quietly.