Just as the light turns green before a race, press X and your driver will get a turbo boosts and also start off with an almost full turbo bar.
Go to the Secrets Shop, and select the Scan for Secret Characters option. If you have the right files, you can unlock new drivers. Make sure you have the right game file on your memory card.
If you have a save file from Ratchet: Deadlocked on either memory card, you can unlock a skin for him in Exhibition Mode. Go to the Secerets Shop, and click on scan for data. Same method used for Jak skins.
To get to the other cups you: