I just bought a carbon fiber endpin shaft from Bob’s House of Basses. (Just the endpin – not the collar and assembly.) I love it! Yes, it will have to be replaced every so often since my standard Goetz collar screws slightly into the shaft but I can see it lasting years. I’m impressed with the sound difference – I didn’t think it would make such a difference. The bass definitely seems to vibrate more. Or I could just be crazy. Either way, I’m very happy with this little modification.