I'd say 25-35k, as-is. The mods on it are great. The skin was very popular for a while, but the market got flooded with a lot of them out of the buried treasure things. They haven't been easy to sell for a while, but gold and q9 can still find a buyer.
That's my guess - GL!
EDIT - I really don't recommend adding mods to a weapon to increase it's sale value. It's true, that a buyer will be more willing to buy if they don't need to mod it. However, there are 2 problems - an added mod doesn't raise the sale price as much as the value of the mod alone, and you really don't know what mods different buyers will want.
(Some of us absolutely loathe sundering mods on our weapons!
So, no, sell the sundering mod and the axe separately. If you have it around anyway, you can offer it in addition to the axe to potential buyers.