i suspect the G2Z will protect the lamp more than its aluminium counterparts without shock isolation, and the G2Z's nitrolon will resist scratches and dings much better. the M2 will still provide more shock protection to the lamp, though the G2Z should be enough for most uses
Due to its size, it probably will get knocked around quite a bit, inadvertently. I'm sure SF engineers have factored this into the design of the light.
Having said that, they sell replacement LA's for a reason...