whats your modding level?
try adding these two moduletags maybe to the Strategy Center(?), it's from the "TechOilRefinery". The 1st (004) auto grants the the upgrade.
Then the 2nd (005)effects the prices
"EffectKindOf = INFANTRY" tells what unit types.
"Percentage = -10%" means 10% off sale!
Behavior = GrantUpgradeCreate ModuleTag_004
UpgradeToGrant = Upgrade_CostReduction
End
Behavior = CostModifierUpgrade ModuleTag_005
TriggeredBy = Upgrade_CostReduction
EffectKindOf = INFANTRY
Percentage = -10%
End
Pretty sure this Can stack if say put it on barracks and built a few.
As for Armor, you'll need to check Armor.ini clone one of the inputs is best and adjust as needed. The inputs should be self explanatory. then change the unit's "ArmorSet" to the new armor name.