Spy units affect ally plunder. Lvl 3 forges have a LOWER ally plunder bonus than a lvl 3 guild. The save is true with a lvl 3 sub factory, and a lvl 4 guild. However the new spy buildings have less ally plunder bonus than the T4 troop buildings.
Ok thanks... Is there a way to find your max plunder with spys and attacker combined? I have an attacker calc.