On additional notes :
3. Give Shadow Ring support power a price tag
Probably on a lesser margin than Magnetic Beam, but this is a very useful support power available so early in the game that can do a lot of damage. I think GuardianGI can explain this better than me.
I think it's free because invisibility can be easily countered by having a few units at you base who can see invisible units. You can have a tesla trooper or a clairvoyant or a dune rider or a navy seal at the choke points of your base and detect all invisible units easily. add dogs and spooks to the mix and no invisible infiltrators will get past your defenses.