In the research file, you will see something along the lines of the following:
researchFloatModifiers 3 researchModifier modifierType "ShipMaxSlots" baseValue 0.000000 perLevelValue 150.000000 researchModifier modifierType "IncomePercLost" baseValue 0.000000 perLevelValue 0.093750 researchModifier modifierType "ShipMaxSlotLevel" baseValue 0.000000 perLevelValue 1.000000
Change the value of "IncomePercLost" to 0.0000 and there will be no upkeep cost.
where do i find this and how do i edit it? with note pad like gameinfo ?