Go to 'Sound Test' submenu and press L1 + R1 + Triangle together to unlock 2 new songs to listen to during the game.
You must defeat all rivals before unlocking these.
Unlock Bunta Fujiwara at Akina Downhill:
Defeat Project D Takumi at Tsukuba.
Unlock Project D Keisuke at Tsukuba:
Defeat all available rivals.
Unlock Project D Takumi at Tsukuba:
Defeat Project D Keisuke at Tsukuba.