Rubber or Urethane?
Big question this subject. Originally manufacturers did not have the modern day urethane materials available so rubber was their only choice (sometimes case steel or bronze). Rubber can be pretty soft and in some cases be the cause of unexpected early replacement especially on Australian roads. Urethane is a much more suitable and higher wearing material and generally we fit more urethane than ever before however in some cases we still advise the use of rubber.
There are lots of debates about either rubber or urethane, the truth is ultimately down to economy of wear and cost of replacement so do not panic, just ask and we will advise through our vast knowledge which is better for your application. Oh! and by the way that oil leak coming from your steering rack or engine bay that you keep meaning to get fixed is a real enemy for bushes. So if you have any leaks always get them fixed as soon as you see them.