Lava Rocks

I can't imagine they'd be all that useful in a WSM, they are pretty steady out of the box.
That being said, I do use lava rock in my Binkmann Trailmaster horizontal smoker to try and even out side to side temps. I remember reading a post from someone saying that all lava rock was good for was dissipating heat so it wouldn't be good to use in a smoker. I might not be the sharpest knife in the drawer, but don't you first have to retain heat to be able to dissipate it? Kinda sounds like what you want in a smoker, no?