The Bug (officially named the Beetle) is a subcompact car produced and designed by Volkswagen (VW). It is noted for its unique curved styling. Although not generally considered a high-performance vehicle, owners can modify their Bugs for performance applications, including drag racing. There are many aftermarket parts available for the Bug, many of which are designed to increase the horsepower output of the vehicle.
Replace the factory cold air intake system with a performance cold air intake system. Installing a performance cold air intake system increases horsepower by allowing more air to flow into the engine. Cold air intake systems are typically the first performance modification that most Bug owners make due to their relative affordability and general ease of installation. Cold air intake systems also have no drawbacks other than a slight increase in engine noise.
Replace the factory exhaust system with a performance exhaust system. Installing a performance exhaust system increases horsepower by allowing hot air to exit the engine bay more efficiently. Performance exhaust systems are a popular modification because they make the vehicle sound more aggressive when accelerating. Note that performance exhaust systems are banned in some states because they increase CO2 emissions.
Install a supercharger kit. Supercharger kits compress air and force it into the engine, which provides a massive boost in power. No single modification will produce a boost in power that can match that of a supercharger, but they are not without drawbacks. In addition to being costly and generally requiring professional installation, supercharger kits drastically reduce your vehicle's fuel economy and put significantly more wear on the other components of the vehicle, including the tires, brakes and suspension. Supercharger vehicles typically do not last as long as naturally aspirated (non-supercharged) vehicles.