On any level during racing pause the game and
  HOLD L1 and press Square, Circle, Circle, Square

Put in the code TRANSMIT
  

Put in the code SCOPE

  

Put in the code TARGET

  
  
All multiplayer Characters

  

  Put in the code Party
  

  Put in the code HEADCASE

On any level during racing pause the game and
  HOLD L1 and press Square, Triangle, Circle, Square, Square

Put in the code HIGHRISE

Put in the code TRACTION