In the Gran Turismo 5 Prologue game for PS3, you can unlock the Quick Tune options so you can change the weight, gearing, horsepower, and aerodynamics of your car. This will allow you to tune a car down so it will have the proper points for a race, and it will let you tune a car up so you’re not at a disadvantage as well.
To unlock the Quick Tune options, you just need to win all of the races in the A Class.
