This is the build I'm running. I didn't mean to take the armor off the arms (as I took the number in your build and put it on the arms without realizing there was +17 there), but I find my torsos are big enough in a crab I get those shot off before my arms in most cases. So I sacrifice a DHS and a bit of arm armor to go for CASE and upping the engine to 320 (the decision was economical because I have 4 STD 320s in my inventory at the time of building this and 0 STD 315s).