Professional mode:
Select arcade mode, then highlight the "Hard" selection on the difficulty selection screen. Hold L1 + R1 until it changes to "Professional".

Corvette C5R
Simply beat 50% of the simulation game and you'll be given a Corvette C5R.

Team ORECA Dodge Viper GTSR
Win all Golds in the Amateur League.

Dodge Viper [Submitted by:Brian Burgoyne ]
To get a free Dodge Viper team Orca, beat all the courses in the amiture league.

Gran Turismo All-Stars prize (Amateur League)
Win the Gran Turismo All-Stars in the Amateur League to unlock the Mine's GT-R-N1 V-spec and Raybrig NSX.

Toyota Sprinter Truendo GT-Apex:
Successfully complete the Sunday Cup with gold medals in all three races to unlock the Toyota Sprinter Truendo GT-Apex.

Mazda Eunos Roadster:
Successfully complete the Cupman Cup with gold medals in all three races to unlock the Mazda Eunos Roadster.

Mazda Roadster RS:
Successfully complete the Spider and Roadster cups with gold medals in all races to unlock the Mazda Roadster RS.

Nissan Silvia K's 1800cc:
Win the Beginner FR Challenge series to unlock the Nissan Silvia K's 1800cc.

Silver Honda CRX Del Sol SiR:
Win the Beginner Race of NA Sports series to unlock Silver Honda CRX Del Sol SiR.

Bonus tracks:
Successfully complete each tier of tracks in arcade mode on any difficulty setting to unlock the next tier of tracks:

Tier 1:
Super Speedway, Midfield Raceway, Smokey Mountain, Swiss Alps, Trial Mountain, Midfield Raceway II.

Tier 2:
Smokey Mountain II, Tokyo R246, Grand Valley Speedway, Laguna Seca Raceway, Rome Circuit, Tahiti Circuit.

Tier 3:
Swiss Alps II, Trial Mountain II, Deep Forest Raceway II, Special Stage Route 5, Seattle Circuit, Test Course.

GAMESHARK CODES: [Submitted by: CV1]

MASTER CODE (MUST BE ON).
EC87829C 143062C

TEN TRILLION DOLLARS $10,000,000,000,000.
1C041124 1456DEAD
1C041120 D26487A5

1c0227381456e7a5 [Submitted by:jeroen ]
This a code for I-a license to unlock this cheat you must have A x-ploder ore something like that

Quick HP boost
For a quick HP boost, immediately after buying a new car in sim mode...take it to the garage and change the oil. should give a some free horsepower!

Get Cash [Submitted by: Erik Arruiza]
After winning amatuer NA race save to memory card two then go back to the amatuer NA then save to memory card one then dont spend money.

Motorbike
L1, R1, R3 (push right analogue stick in), R2 THEN X, X, Triangle. Do this at car selection screen in arcade