One thing I've been doing is dialing up the number of hairs (a lot) and decreasing the thickness in Carrara. Seems that FirePlug renders the hair nice and soft, but when it gets into Carrara it looks like a wire-bristle brush. Of course I have yet to work with a render engine that will natively get that lovely backlit look. In real hair it happens because light actually bends around fine hairs, creating a sort of SSS effect in the outer layers (and real hair is also slightly translucent anyhow). By the by, I'm pretty sure there is a "delay" setting for the "wriggle" element. I know I've seen it -- shouldn't be too hard for you to find.