A few questions, Brovo:

1. Can I only upgrade my main weapon (shotgun) as a Grunt, or can I upgrade my side pistol to make it more effective instead?
2. For clarification, every PC has their own apartment and they're all living in the same complex?
3. What does my promotion mean in the story besides the gameplay element of being able to officially order NPC soldiers?
4. Will promotions and rank in general play a major part in later missions?