Fleabay have loads of SME parts (the heavier counterweight [for the S2 Imp model] works well if you want to increase the mass of the tonearm - I can't remember which arm you have), but I don't know if SME supplied parts are very much dearer...
Instead of the blac-tac between cart and headshell, try a piece of green card-table baize instead. It transformed a V15 III I tried it with in an SME headshell.
Tear down these walls; Cut the ties that held me
Crying out at the top of my voice; Tell me now if you can hear me