PC on Vampiric Shadowbow of Enchanting plz

Hi guys this is my first request for a pc. The stats are:

Vampiric Shadow Bow of Enchanting (gold):

Piercing Dmg:15-28 (req9)
Dmg 15^50
Life stealing: 5
health regen: -1
Echantments last 20% longer

How much could i get for that? Would I get more if I swapped the enchantments 20% for a +30hp? If so how much more? Thx in advance to you all

dont mod it,it wont rise the price....around 20k,its very very hard to sell any shadow item these days,eaven if its perfect