The rubber is critical in a damper. I stay away from small "race" or "performance" company dampers that are made in china. I have found in general, rubber that is formulated or designed by Chinese companies is terrible. A very large reputable US manufacturer (like OEM or Dorman) will be good about making sure the correct rubber technology is in place even if made in china and I have had good experience using these. Australian units tend to be good as well.