My 2009 Clubman S has developed a clunking noise from the rear when I go over bumps. I've replaced the rear sway bar end links but the noise is still there. While I had the car up on jacxkstands I tested all the bushings for movement,and the big offender were the rear trailing arm bushings at the chassis. Does polyurethane work well for this bushing on the street? It's my daughters daily, so going super stiff isn't needed.