I haven't seen this addressed anywhere. Is there a rule that says you have to physically have an upgrade card for a ship to take that upgrade? For example, I have a Falcon and a Slave I, so I have two Engine Upgrade cards. Can I equip four X-wings with engine upgrade cards, as long as I pay the point cost and meet the normal upgrade requirements?
It seems to me that limiting the upgrades to only the cards you physically have places an unrealistic limitation on the game. Why should the squad in the game be limited to the upgrades I can afford to buy in the real world? Any thoughts?