Won Gold on all Playlist 1 Challenges in Co-op Mode.
Playlist 1 has a total of 3 challenges:

(1) Rio Speed Check

Gold Medal Requirement: 260.00 MPH (Solo) - 520.00 MPH (Co-op)
Preferable Car/s: Dodge Daytona 1969
Preferable Mods: Double Acceleration - Top Speed - Super Boost


(2) Buenos Aires Survival

Gold Medal Requirement: 05:00:00 min (Solo) - 05:00:00 min (Co-op)
Preferable Car/s: Dodge Daytona 1969
Preferable Mods: Double Health - Double Armor - (Explosive Ammo (as a gunman) OR Top Speed (as a driver))

(3) Rio Self Destruct

Gold Medal Requirement: 350,000 PTS (Solo) - 600,000 PTS (Co-op)
Preferable Car/s: Dodge Daytona 1969
Preferable Mods: Double Health - Top Speed - Double Acceleration