the dmg is added to "base dmg", which is really the same as having that much more dmg on the weapon. a +400 grief zerker, for example, is like having 424-471 dmg. conc barbs, like zealots, usually don't need to worry much about weapon range, so i suggest using grief in a phase blade. it's just giving up a small amount of dmg for a lot more speed, not to mention u never have to repair it. also, phase blades look so damn cool.