Milltek Sport Audi S3 Saloon RACE OPF/GPF Back Exhaust System (8Y)Milltek Sport Race OPF Back Exhaust System for the Audi 8Y Saloon transforms the sound of the S3's 2. 0L TFSI engine whilst retaining the factory OPF filters. This keeps the vehicle completely emissions compliant with ECE approval. As this is the Racing exhaust system, it's non resonated to achieve optimal airflow and extract the maximum amount of noise. Your new Milltek race system will make a noticeable difference with power gains, improved noise