Extract the TWO folders named "Modern Warfare Heists Tracks" and "Modern Warfare Menu Tracks" straight into 'mods' folder!
OR
In the PAYDAY 2 game directory, open the 'assets' folder and then open the 'mod_overrides' folder (create one if required).
Extract the TWO folders named "Modern Warfare Heists Tracks" and "Modern Warfare Menu Tracks" and drag these TWO folders into the 'mod_overrides' folder.
Launch Game, go to your sound settings on the main menu then CUSTOM MENU TRACKS...
MAIN MENU SCREEN - MW Menu
LOAD-OUT SCREEN - MW Expendable
HEIST RESULT SCREEN - MW Victory
HEIST FAILED SCREEN - DO NOT TRUST SHEPARD!
PICK CARD SCREEN - MW Draw
On LOAD-OUT Screen you can change the track to custom track! Toggle this on and select Modern Warfare Heist Tracks. Music automatically changes in-game depending on situations.