On empty race days, create a sprint race and enter it. When it starts, use all your nitro and just keep pressing L near the redline. You will usually win about 95% of the time.
On empty race days, host a Class 1 sprint race. Bet all your money on the Dodge Viper, which will usually always win. If there are two Vipers, do not make a bet.
Extreme nitrous series
To unlock the extreme nitrous series in arcade mode get 100% in career mode.
Unlock all Arcade Mode cars and tracks
Go to the Extras menu. Select the Cheats menu. Type the code PIES.