Cars that can be modified

A race modified Lotus Elise 111R.

Racing Modifications are modifications that make cars more suitable for racing. First appearing in Gran Turismo, they have made a comeback in Gran Turismo 5. Typical modifications include replacing the body with a new, more aerodynamic one, changing the rims to lighter rims, adding racing decals for aesthetic effect, and in GT5, stripping out the interior and adding a rollcage, racing seats, a lighter dashboard, and a new racing steering wheel.

In Gran Turismo 5 however, all previously-installed upgrades are removed after installing the racing modifications, but the racing modification themselves will also include Full Custom Suspension and Full Custom Transmission upgrades as well as making the car lighter than the usual weight reduction upgrades (Stage 1, 2 and 3 + Window Weight Reduction Upgrades). The ability to adjust the front and rear downforce aerodynamics are also available on all RM cars.

The racing modification also comes with sports tires and will come in a default white paint job with various racing livery and a customizable race car number. All RM cars can also be painted with any paint chip color you have available through the GT Auto Paint feature.

It is recommended that the player install the racing modifications before installing anything else, otherwise, the player will have to buy any previously purchased parts all over again, which means that they will lose money spent on previous upgrades and ultimately end up spending more money than is necessary.

Once the Racing modification is purchaced, there is typically a handful of upgrades available on top of th the ones that come with the Racing Modification, depending on the car being tuned. This will typically include a way to increase the horsepower by way of Engine, Turbo and/or supercharger and the ability to purchase other types of tires such as Racing Medium and/or Racing Soft. Some models such as the Impreza, Lancer and Elise can also make use of Dirt and Snow tyres for Rally type races. The Chassis Reinforcement upgrade is also available for RM cars.

Obtaining an RM car is also the only way, or at the very least one of the easiest and cheapest ways, to purchase a fully fledged "Race" Car, especially if you are in the Lower levels of A Spec and/or B Spec, since their base models are always available through the dealerships and they range from level 15 all the way down to level 0. It is just a matter of saving enough credits to make the initial car purchase and the Racing Modification upgrade.