All 8 tracks:

Go to Arcade Mode and enter the "Bonus Items" option. You should see the letters A, B, and C above each of the levels given. As you do the following, they will be covered with a blue, yellow, or red dot. To fill in the four big question marks, go back to the main Arcade Mode screen. Then, go to "Single Race", choose any difficulty level, and place first in each of the four original levels with an A class car (ex: Mitsubishi GTO), a B class car (ex: Mitsubishi Eclipse), and a C class car (ex: Honda Civic 3-Door). After you have done this, go back to the "Bonus Items" menu and the four big question marks should be filled in with these levels: Autumn Ring, Deep Forest, SS R5, and Grand Valley Speedway. That makes 8 tracks!

New Dealers:

Beat all 8 tracks under 'Easy' and get 4 new car groups - Toyota, Subaru, The New Dodge, and TVR.

Ending Movie:

Beat all 8 tracks under "Normal" and get an ending movie (credits).

Hi-Res Mode:

Beat all 8 tracks under "Difficult." Hi-Res mode makes the graphics less pixels and makes the game have better sound.

Chrysler Concept Car:

Get all gold medals in the B Class license test and you'll get the Copperhead. You can also get it by getting first in the UK vs. US championship.

Toyota TRD3000GT:

Get all gold medals in the A Class license test.

Nissan Nismo 400[R]:

Get all gold medals in the International A license test.

Extra Parts:

Buy one car and outfit it with all the parts you want then save the game. When you have enough money buy a second car of the exact same model. Get in it and go race. When the change parts screen comes up go into it and you can change its parts to the ones on the first car. Note - this only works for parts, not for weight reduction or racing modifications. You can then sell the car for more than you bought it for

Secret Cars:

Toyota Chaser LM Edition - Win the GT cup.

Dodge Viper GTS-R LM Edition - Win the American-Japanese cup.

Mitsubishi FTO LM Edition - Win the American-Japanese cup again (best if done right after the first).

TVR Cerbera LM Edition -Win the British-Japanese cup.

Honda del sol LM Edition - Win the British-Japanese cup again (best if done right after the first).

Nissan S14 Silvia LM Edition - Win the SS Route 11 race.

Totally customizable Nissan Nismo GTS LM Edition - Win the reversed SS Route 11 race.