Gran Turismo 5 Prologue PS3 Game Cheats

Unlock S class events:
Complete the A, B, and C class events with a bronze medal or higher rank to unlock the S class events.

Unlockable cars:
Unlock the listed car by completing the corresponding task:

BMW Concept 1 Series tii '07 - Win all B class races.
Daihatsu OFC-1 - Win all C class races.
Ferrari F2007 - Win all A, B, C, and S class races.
Nissan GT-R Proto 05' - Win all S class races.Nissan Skyline Coupe Concept '07 - Win all A class races.

Unlock quick tune options:
Complete all A class events to unlock the quick tune options. The quick tune options allow you to adjust your cars weight, horsepower, aerodynamics and other settings.

How to drift:
Select a car with All or Rear-Wheel Drive. Turn off traction control.
Select tire s1 at the front for AWD
Select tire s3 at the front for RWD

Select tire n3 at the rear for AWD
Select tire n1 at the rear for RWD

Car that are easy to drift:

Audi R8
Ferrari 599
Ferrari F430
Nissan Skyline R35 GT
Mercedes-Benz SL500

Source:http://www.gamingcheats.com