I see that when you reach rank 50 you can begin to unlock "support upgrades" via "armor specializations". It will be a while before I get to that rank, but since I will need to make a choice I'd like to have my decision made ahead of time (instead of stopping matchmaking to do research *gasp*). What support upgrades are unlocked for each specialization? Are there any prerequisites which limit which armor specialization I choose?
This IGN page gives a list of specializations, and for each the page that it links to gives the corresponding support upgrade armor mod that you can unlock. For each specialization, the support upgrade is as follows: