Found this little nugget in the FFG rules forumhttps://community.fantasyflightgames.com/topic/198460-squad-...
The deployment cost of a group is not altered when an upgrade is attached to it. They each have their own separate deployment costs that are both scored when that group is defeated. So, an attachment on a Stormtrooper group would not affect their eligibility for Squad Swarm or Strength in Numbers.
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