for the lore, the mk1 assault suit was made out of what the Stinger ops could get from the super-soldiers they killed. mk2 was created after they raided GRIZZLI a couple of times and had enough material to make offensive suits. Mk1 is still in use by the gaurds at the honeycomb, but mk2 is more common. It is lighter and doesn't have as many features(such as heat signature detection)