It is easy to spend hundreds of pounds or dollars on an RC car at your local hobby store. However, spending more money on a car doesn't necessarily equate to more fun. There are cheap RC cars available for those shopping on a budget. Although these cheaper cars are often slower and smaller than the expensive cars crowding the aisles of hobby shops, they can still be quite fun. With a few modifications, they can be made to perform as well as their more expensive counterparts.
Replace the stock motor and speed control with brushless units. This should be your first modification when dealing with a cheap RC car. Cheap cars commonly come from the factory with slow, dated electronics. Swapping these out for a brushless unit will instantly increase the car's top speed and power. Before you purchase a brushless set-up, make sure the motor is the correct size for your RC car model.
Purchase new batteries to make your RC car perform better. Cheap RC cars typically come with low-capacity batteries that provide poor power and battery life. A high-capacity nickel-metal hydride (NiMH) battery or a lithium polymer pack will give you faster, longer rides.
Switch out the stock tires for ones that match your style of driving. Stock tires usually have multipurpose treads that make them adequate for different driving environments but do not excel on any one surface. If you intend to run on the street, get a set of sticky street tires. If you are going to be bashing in the dirt, buy a set of knobby off-road tires. By matching tires to your intended play style, you will maximise the traction and handling of your cheap RC car.
Cut off excess plastic on the chassis of your car with a Dremel-style rotary tool. Do this only to areas that provide no structural support, such as a battery tie-down or speed control tray. Reducing the weight of your car will increase top speed and acceleration and costs nothing to modify, as long as you have a rotary tool handy.
Always wear safety glasses when cutting with a rotary tool to prevent eye injuries.