Vampire Shadowslayers

Could these be switched to a non-dynamic model?

Especially given they like to attack from stealth, having 2 to 6 of these dynamic model creatures spawn in can cause a rather large lag/hiccup on lower end systems. And given they are high damage creatures (sneak attacks), those several seconds of video lag trying to render a whole spawn of them can pretty much mean a lag right into the greathall for mid level PCs without crit immunity or super high ACs.