Super Sonic Mode 
     When  in  Washington  DC find the Lincoln Memorial and pull up to
his  feet.  Using  the  right  thumb stick, look up at him and hold it
there  for  20-30 seconds. The screen should go black and white. Drive
away and you will notice that you are in super sonic speed mode.

Unlock New Cars 
    Fulfill the criteria listed below to unlock the indicated vehicle:
    Paris Bus: Win the first three checkpoint races in Paris.
    Washington Bus: Win the first three checkpoint races in Washington.
    Fire Truck: Win the first six checkpoint races in Paris.
    Cement Truck: Win the first six checkpoint races in Washington.
    Armored Car: Complete the Paris security guard job.
    Freightliner Century Class S/T: Complete the first six blitz races
    in Washington.
    Hummer H2 SUV: Complete the Washington Salesman job.
    FLE: Complete the Paris Delivery Guy job.
    Limousine: Complete the Paris chauffeur job.
    Cadillac Escalade: Complete the Washington Limo Driver job.
    Ambulance: Complete the Paris Paramedic job.
    Taxi: Complete the Paris Taxi Driver job.
    Paris Police: Complete the Paris Police Officer job.
    Washington Police: Complete the Washington Police Officer job.
    Chrysler PT Turbo: Complete the Washington Rental Car Driver job.
    1959 Eldorado Seville: Complete the Washington Pizza Deliverer job.
    Mini Cooper S: Complete the first three blitz races in Paris.
    Chevrolet SSR: Complete the first three blitz races in Washington.
    Saab 9-3 Turbo: Win the tenth checkpoint race in Paris.
    Audi TT: Complete the Paris Special Agent job.
    Chrysler Crossfire: Win the tenth blitz race in Washington.
    Audi S4 Avant: Complete the first six blitz races in Paris.
    1967 Ford Mustang 2+2 Fastback: Complete the Washington Stunt
    Car Driver job.
    Chevrolet Corvette Z06: Win the tenth checkpoint race in Washington.
    Lotus Esprit V8: Win the tenth Paris Blitz race.
    Dodge Viper SRT-10: Complete the Washington Private Eye job.
    Koenigsegg CC: Complete it ALL.

Unlock all cars and missions (submitted by G money):
     At  the main menu, click and hold the Left Thumbstick. Then enter
the  following  code:  L  trigger,  R trigger, L trigger, L trigger,
L trigger,  R  trigger,  R  trigger,  R trigger, L trigger, L trigger,
R trigger, R trigger
     If  you're  doing it correctly you have unlocked all cars and all
missions.