The song to be featured in this trailer is titled "Arm In Arm (Shy Child Remix)" by The Boggs, a band based in New York. The new trailer indicates in subtle ways how the passage of time might affect the game.
Additional info from Rockstar:
1.All footage is captured in real-time on a next generation gaming console.
Running on Rockstar’s proprietary next generation game engine, 2.R.A.G.E., allowing for an unprecedented level of realism and interactivity.
3.Game is using euphoria, a fully procedural animation package created by NaturalMotion.