The mirrored Ring and Amulet problem

Let say this is my Amulet:

+80 life
+50 dex
+1 to all skill gem
+30 chaos resistance

And i need all of those stats for my build

If i put it in the Mirror Mechanic my Amulet will become

+160 life
-100 dex
+2 to all skill gem
-60 chaos res

I never want my to have -100 dex and -60 chaos res for my build just to gain +80 Life and +1 to all skill gem

My power level doesnt change at all after i Mirrored the item and there is no going back when the item is Mirrored, so no way i would Mirror my item for nothing

You are supposed to do it with an item that has 2 mods you don't mind going down and the life and skill gem you want to go up then click and pray.