K&N Audi A4 1.8L Turbo 150BHP Performance Intake KitK&N 57i Series induction kits are specifically designed for each different vehicle and will free your car from the size restriction that comes with the factory air box. These economical kits can take a variety of different forms based on vehicle characteristics and available space under the hood. Each kit is designed to provide power throughout the RPM range. The extra surface area of these open air air filters provides even more airflow at lower