Go to Championship mode. When at the character selection screen, go to password. Type in kkbhggg$m3ts. You should now have a Afro Thunder with 100% stats.
To get Michael Jackson
At game selection screen highlight arcade and hit left, left, right, right, left, right and L and R.
To get Rumble Man
At game selction screen highlight championship and hit, left, right, left, right, right, left, right, left and L and R.
To get Shaq
At game selection screen highlight survival and hit left, left, left, left, right, right, left, left, right and L and R.