the rubber seat/bushing thin at the top of the shock mount has a void underneath that big brass washer thing. stiff shocks/or slightly over tight bolt will cause the empty space to collapse under movement. Many people have put shims in there to remove the void. I myself just cut an 1/8" thick piece of neoprene to fill the gap and presto, no more noise.
heres the how-to to show the parts im talking about
http://www.focushacks.com/index.php?modid=28
heres the how-to to show the parts im talking about
http://www.focushacks.com/index.php?modid=28