[CodeCat]

... get a unit's turret turn speed to increase with an upgrade or with a veteran bonus? Is it even possible?

[DeeZire]

You would have to do it by upgrading the weapon set, say changing the weapon from Primary to Secondary, and allocating the turret parameters to the new (Secondary) weapon in the AIUpdateInterface module. That way you could have different turret characteristics by assigning the Primary weapon to the turret and the Secondary weapon to the AltTurret.