Press Up, Down, Left, Right, Left, 2, Up at the title screen.
Rock Hard mode:
Press Up, Down, Left, Right, Left, 2, Up two times, 2, Up at the title screen.
Press Up, 2, Down, 2 two times, Left, 2 three times at the title screen.
Always finish in first place:
Start the Breakfast Bends level as usual. When the other cars race off, turn around and complete the lap, traveling in the wrong direction. When you cross the finish line you will hear a jingle to indicate the code has worked. Whatever happens, you will now finish every race in first place.