QUOTE(dare0021)
So, what does it upgrade besides nuke damage, building armour, and psi storm damage?
I explicitly stated that nuke damage is NOT upgraded.
Things that are upgraded include:
Worker damage (SCV, Probe, Drone)
Building attack damage (Photon Cannon, Sunken/Spore Colony, Missile Turret)
Building armor
Spells (Psionic Storm damage, maybe others)
Infested Terran/Scourge/Spider mine damage