Sound Test
On the Mode Select screen, press Select until either "Edit Team II," Set Up," or "Watch" modes are lit up. Hold the L and R Buttons, then press Start to access the sound test screen. Press any direction to change the number, and press B to listen to the desired music.
Speed Mode
When you are choosing your team, while holding the L and R Buttons, press Start to begin the game. This trick will more than double the speed of the players on both sides.