The Corporate Warfare Add-on for Saints Row 2 has 5 achievements worth 125 gamerscore.
Complete the Corporate Warfare mission arc
Play the Stuntmen Co-op game once
Win 20 rounds in the Stuntmen Co-op game
Your team needs to hold all tag spots at one time in a Strong Arm match on Xbox LIVE
Won 10 Gangster Brawls or Team Gangster Brawls on Xbox LIVE