A performance intake system upgrade involves replacing the stock air intake system on a vehicle with an aftermarket intake system designed to improve the engine's performance. The stock air intake system is typically designed to be quiet and efficient, which can limit the amount of air that enters the engine, and therefore, limit the engine's potential power output.

A performance intake system is designed to allow more air to flow into the engine, which can increase horsepower and torque, as well as improve throttle response and acceleration. The system typically includes an air filter, an intake tube, and a heat shield, and may also include other components such as a velocity stack, an air flow meter, or a bypass valve.

The air filter is a key component of a performance intake system, as it is designed to filter out contaminants while allowing more air to flow into the engine. The intake tube is typically made from a material that is less restrictive than the stock tube, allowing more air to flow through. The heat shield is designed to protect the air filter from engine heat, which can reduce the intake air temperature and further increase performance.