Bang for the buck

I've got some money to spend but it must be spent wisely. I would like to know what would give a better result. A new tonearm or a new platter/clamp?

I have a Gyrodec SE with an Audio Note Arm One and new Sumiko Blue Point EVO III.

Looking to u/g the arm or platter or possibly only the clamp. Any suggestions on which would give me more sound?