Access all GT2 vehicles:
     In  Championship  mode,  at  the  GT2  circuit  menu, (Teams/Even
Select,  Save  Game, Main Menu) press Z, Right, Z, Z, Z, B, C-Down, A,
Right, Start on controller two.

All Tracks and Cars:
     Start  a  new  game  in  championship mode and enter your name as
"races the best." At the next screen appears press Left, Right, Right,
Left, Down, Up.

Blurry Mode:
     During  normal gameplay press this with the second controller: B,
Left,  Up,  Right,  Right, Right, A, Start, Start, Z, Right, A, Up, Z,
Down-C, Start.

Change Car Color:
     Press Z at the car selection screen.

All Sydney tracks:
     Remove  the  memory  pak  from  the controller. Then, start a new
championship and enter "FROZENSKY" as a name. Accept an offer from one
of the two teams. Once you have accepted, return to the main menu, and
select a quick race. Choose one of the race modes, and you should have
access  to  any  of  the  Sydney  tracks. Return to the main menu, and
insert the memory pak. Load your current career to restore all of your
game  settings.  Save your career. Then when the game is reloaded, all
six variations of the Sydney tracks should still be available

Mirrored Tracks:
     Press Z button to select a track instead of the A button

Pink car:
     Start a new game in championship mode and enter IGN64 as a name.

Red Track Marks:
     While Racing Press: B, L, V, D, R, R, R, D on the d-pad.

Custom Car in End Sequence:
     Once  you  finish  the  GT2  Circuit  you  will  get a GT2 Ending
Sequence option in the options menu.

Get Falcon Interceptor:
     Finish  the  game  with a gold trophy for all events. Go back and
start  a  novice cup race and defeat the Falcon Interceptor car in the
novice  cup  races.  Now it will be available on the Team Select sceen
under Boss Racing

Speed trick:
Start the game normally in any mode.
Select manual transmission.
Accelerate your car over 100km/h.
Then turn your car to reverse and hold it reverse.
Your car starts to accelerate very fast.
You can reach over 400km/h speed but your car is hard to control. 

Tracks:

Las Vegas CR Track:
     Use the Stallion C car to win at the Hawaii A Track (2 laps)

Sydney CR Track:
     Use the Manta C car to win at the Las Vegas A Track (3 laps)

Hawaii C Track:
     Use the Rage C car to win at the Lisbon C Track (3 laps)

Kyoto B Track:
     Use the Swift C car to win at the Lisbon CR Track (4 laps)

Kyoto AR Track:
     Use the Rage A car to win at the Hawaii C Track (2 laps)