Move Screen Position
Using controller 2 during a single player race Hold L + R + Start then move the Analog Stick

Get the Squirrel Car
Finish the Light Series

Mountain Dew Pickup
Finish the Heavy Series

Get Five O Car
Finish the Sport Series

Get Semi Truck
Finish the California Cup

Get Predator Car
Finish the Sport series using the Five O car

Get Mano Car
Finish the Sport series using the Predator car

Get Fuji and Clover Tracks
Finish the Sport Series week two

Get California Track
Finish the California Cup Week 5

Get Oval Track
Finish the Heavy Series Week 2

Get Insect Series
Finish the Light series using the Squirrel car

Get Forklift Car
Finish the Light series using the Insect Car

Get OL' Truck
Finish the Heavy series using the Moutain Dew Pickup

Get Dozer Truck
Finish the Do The State Mode with the Semi truck

Get Camper Truck
Finish the Heavy series using the OL' Truck

Get Mirrored Series Tracks
After picking practice mode choose the mirrored version of any track. After starting on the track exit and start a race in series mode. You now have the mirrored version.

Get San Andreas Track
Finish week three of the Heavy Series

Change Fog Color
After picking a non-series race hold L + R + C-Up + C-Down + C-Left + C-Right + Down as the screen fades and keep holding til the track select screen has fully appeared. Now you can press RIGHT until a fog adjust option appears