As far as strength of the actual arm itself, exclusive of type/style of bushings/joints used, I would expect something hewn (CNCed) from BILLET, even aluminum alloy billet, to be ultimately stronger than even chromoly which is welded together (I will let others comment on the quality of said welds, or not).
I am NOT a materials engineer (any on here, who can chime in on this?), so not too sure at what point/PSI level the factory steel, and DNA chromoly arms would bend, and if that PSI level is above, or lower than, where the billet alloy ones would actually shear.