I personally enjoyed the quest to obtain the amulet, but the amulet itself was very underwhelming given the quest and the lore behind the amulet. The lore suggest the amulet is incredibly powerful so powerful in fact that broken into three pieces it still gave the Gauldur brothers significant power. 

The original amulet increased Health, Magicka, and Stamina by 30 points which is hardly worth it.

I increased it's power to something Gauldur's three sons would have killed him over.

It now increases Health, Magicka, and Stamina by 150 points, increases Health, Magicka, and Stamina regen by 25% and Resist Magic by 25%

Optional Versions Available:
Enhanced Gauldur Amulet 50: Health, Magicka, and Stamina by 50 points, increases Health, Magicka, and Stamina regen by 25% and Resist Magic by 25%

Enhanced Gauldur Amulet 100: Health, Magicka, and Stamina by 100 points, increases Health, Magicka, and Stamina regen by 25% and Resist Magic by 25%

I provided these just in case you felt the 150 was overly powerful. I use a lot of difficulty and combat mods so for me it's not that powerful

New Arch-Mage Version Available!
Gauldur was an incredibly powerful Breton Arch-Mage his amulet should reflect that.This version is designed specficly for mages as I have removed the helth and stamina buffs in favor of more magic bonuses

Enhanced Gauldur Amulet Arch-Mage Edition: Magicka by 150 points,Magicka regen by 50% and Resist Magic by 25% Now all spells cost 15% less to cast.
  

I tried to make it as lore friendly as possible without making it so vastly overpowered.