Different mass at bar end will change the fundamental frequency at which it resonates. It's new max amplitude will depend on the resulting energy into the system and the new "tuning" characteristics as it sits in your hands. Bottom line: different frequency (lower with more mass) and a different amplitude...not necessarily better (a completely subjective evaluation anyway).
That said, some folks around here swear by their bar end changes. Unless you're a well-exercised structural engineer, the only way to find out if the change suits you is to try it.
If you do, let us know what you think.
W2