Instructions
Start up Gran Turismo 5 on your PS3, and navigate to the main GT Life screen. Here you will see such options as A-Spec and B-Spec races, dealerships, etc. Select the car from your garage that you wish to customize; then navigate to the GT Auto section--it's a rectangular box in the middle of the screen. Select this option, and you will be taken into the first of Gran Turismo 5's customization zones.
Look at the bottom of the screen when GT Auto loads and you will see nine parameters for car customization. The first two are simply Car Wash and Oil Change. The former will give your vehicle a glossy look as well as help slightly with aerodynamics, while the latter will restore lost horsepower from the simulated wear on your vehicle's engine.
Navigate right and you'll see the more extensive customization options. The next two in line are marked by paint guns and, fittingly, are options to paint your vehicle's body and wheel color, respectively. Select these options and browse colors on the pop-up screen to see your car's body paint and wheels change color. Select and confirm a color option to apply it.
Scroll to the right once more to select the Change Wheels option. This differs from the previous option in that it allows you to select many different styles and sizes of wheels from various manufacturers. Navigate the different options to see them appear on your vehicle before purchasing. Once purchased, note that the color of your wheels can be changed in the Paint menu discussed above.
Scroll right once more to the menu titled Aero Kit. Here you will be able to change the appearance of your car by installing parts like bumpers and wind spoilers. These additions will also affect your vehicle's performance by adding downforce or reducing wind resistance.
Notice that the remaining three menus don't allow selection of individual customizations. The first menu is Engine Overhaul, which will restore lost horsepower to your vehicle if it's accumulated enough simulated miles to hurt performance. The next is Restore Body Rigidity, which restores lost handling ability due to accumulated miles. The final option is Racing Modifications. This option is not available for all cars. It adds a slew of general "racing" modifications to your vehicle that will increase performance all around, including power and handling.
Navigate out of the GT Auto menu and scroll right to the Tuning Shop menu. Select this option to purchase numerous performance modifications for your vehicle. You will notice at the main Tuning Shop screen an entire list of options, from chassis upgrades to turbo kits. Select these individual options and browse the available parts to see descriptions thereof and the ways in which they will improve your vehicle, such as before-and-after horsepower numbers. In the Tuning Shop you can also fine tune specific vehicle parameters, such as handling characteristics and gear ratios, once upgrades are performed.