I switched the brimstone eaters with gemfinders, (yes less damage) but the elite graboids instead of phoenixes start out burrowed, thus immune to even more, and grow into shreikers! not to mention the earth quanta can burrow the shreikers, and burrow the pests...
I think its got more "ability to win" but its definately a little slower... (not by much)
on second thought... the shreikers kinda flunk... they cost too much to get out.