2 pieces of mutagenic for me did 250 dps on overking, for example. BUT we had tons of issues with the flames and people getting ported, though never once was it me i'm just not sure if they are a good idea for that fight.
i have been using the bp / belt for a bit on anything i mass pull, doesnt add a ton but defintiely the most dps out of any bp / belt i got (until i get a sash of pain i think)