If your guild is downing saurfang on a regular basis, try to get Ramaladni's Blade of Culling, that would more than make up for the expertise you lose switching to the dps helm. If not, Keen Obsidian Edged Blade from Onyxia's lair would also put you well over the expertise cap, at the cost of a significant amount of armor penetration, assuming you can get a group for it. However, that would allow you to equip the 245 badge helm for dps, which has about 30 more armor pen rating than the Tyrannical Beheader, not to mention gain you a respectable amount of crit. Also- drop the Hit trinket. It's an absolutely terrible trinket, I'm pretty sure blizz put the 245 badge trinkets in as a joke to see how many people would waste the emblems on them. Even a trinket from the emblems of heroism would suit you better (The Mirror of Truth is a pretty good one). If your guild is downing the first wing of ICC on a regular basis you'll eventually get the Whispering Fanged Skull, which is awesome. You've got a ridiculous amount of hit even without the trinket but replacing it with something better should be your first priority.