Popular car mods include quicker steering, disc brakes, wider tires and seats and belts. These mods are ideal for vintage cars but can be applied to almost any vehicle.
One very practical mod is to modify the steering wheel to be more responsive to driver input. The driver can swap in a new steering box for a more responsive car and optionally replace other parts of the original steering such as ball joints and tie-rod ends for more responsiveness. Another popular and simple modification is to put disc brakes on the front of the car. These brakes cool faster than rear disc brakes and also help the car to stop more quickly.
Another simple modification is to add wider tires to the car. Adding wider tires that are no more than 200 treadwear helps the car with acceleration, handling and even braking. The downsides to this modification are that it lowers the car's rolling resistance and wet weather traction. Those intending to drive their car very fast typically replace the seats and the belts inside the car. By adding seats that are at least 2 inches taller than the cushion and a four-point or greater harness, the driver is able to avoid sliding in his chair and can concentrate on driving.