A car's intake and exhaust system play an important role in the engine's performance and power output. The intake system brings fresh air into the engine, while the exhaust system expels the waste gases out of the engine after combustion.

The intake system typically consists of an air filter, airflow sensor, intake manifold, and intake ports/valves. The air filter removes any dirt or debris before air enters the system. The airflow sensor measures the volume of air coming in so the engine computer can adjust the fuel injection appropriately. The intake manifold distributes the air to each of the cylinders through the intake ports and valves.

The exhaust system starts at the exhaust ports/valves, where the waste gases exit the cylinders. The gases then flow through the exhaust manifold and the rest of the exhaust piping before being expelled out of the tailpipe. The exhaust system will also typically have one or more catalytic converters to reduce pollution, as well as an oxygen sensor so the engine computer can monitor exhaust oxygen levels.

Modifying the intake and exhaust system by using performance air filters, intake manifolds, headers, exhaust manifolds, catback exhaust systems, and mufflers can provide several benefits:

Improved throttle response.

With less restrictive intake and exhaust components, the engine can respond faster to throttle inputs since it can flow air and gases quicker. This results in improved acceleration. 

Better fuel economy.

An engine that can breathe more efficiently requires less effort to generate the same power. This can slightly improve fuel efficiency during normal driving conditions. 

Enhanced engine note. 

A performance exhaust system often provides a more aggressive tone from the engine due to less muffling of the sound from the waste gases. This is appealing to many sports car and performance vehicle owners. 

However, modified intake and exhaust systems may not meet emissions regulations in some areas and can increase exhaust noise, which some people may find annoying. But for many automotive enthusiasts, a modified intake and exhaust can provide an enjoyable increase in power and performance with an aggressive engine soundtrack.

In summary, the intake and exhaust systems are crucial components that help a car's engine make power by bringing in air and expelling waste gases. Upgrading these systems with performance parts offers several benefits like improved power and throttle response, increased fuel efficiency, and an enhanced exhaust note, though emissions regulations and noise levels should also be considered. For sports cars and performance vehicles, modifying the intake and exhaust system is one of the simplest ways to gain additional power and driver enjoyment.