Data 3.1
In the area where you fought the two GRADs, you'll be instructed to go up stairs and enter a building. There will be stairs with a large class canopy over them. Get on top of the canopy and follow it to the point where it connects to the building. You'll find the Data on the canopy here.
Data 3.2
While on the rooftops, you'll get to a new rooftop with enemies to your right. When you turn, you'll see a Slider coming towards you and then fly over you. You need to kill him to get this Data but be quick or he'll pass by and won't return.
Data 3.3
After entering the dark tunnels under Denver, you'll have to get past a couple of Mastiffs before coming up a third. After dealing with the Mastiff, get on the left track and then come back the way you came until you hit a dead end. You'll find the data in the rubble.
Data 3.4
After the tunnel section, you'll come to a plaza with a giant set of stairs leading up and away from you. Before going up the stairs, check left and you'll find a small vendors stand. Jump on top, and climb up to the small ledge on the nearby building. Climb up once more to the round ledge just to the right to find this data.
