Get an "S" rank on three races with the same truck to unlock its alternate paint color.
Excite Truck unlockable Cups:
Get an "S" on all Super Excite Race mode tracks.
Unlock the alternate paint schemes for all trucks.
Complete the indicated task to unlock the corresponding truck. Note: The total number of stars you currently have is not tracked by the game and must be manually recorded.
After unlocking Super Excite Mode, get passing grades on all the races in the Bronze, Silver, Gold, and Platinum Cups. Then the Diamond Cup will be unlocked. It is only contains one race. This course is called Crystal Road, and is located on Nebula, way out in space.
Excite Truck unlockables:
When you use your turbo and you engine starts to overheat, drive in water or a puddle to cool it down.
When hitting any type of hill or ramp, tap Turbo(2) (D-pad) in any direction to get the "Extra Turbo Boost". This is helpful for reaching the rings when jumping and to help recover the top spot during the race. It can be used repeatedly, and is helpful when you are about to overheat. You can cover extremely large gaps in the race even when there is not a cliff below you.