Stock air filter assemblies choke your C5 2001-2004 LS1 Corvette's performance before the fact by restricting air into the engine. Let your Corvette breath with this 2001-2004 Corvette SLP Blackwing Cold Air Induction System, the most technologically advanced air intake on the market. Install the Blackwing and you increase airflow by up to 90% over the stock unit. That translates into a gain of 18 hp. The C5 Corvette Blackwing Cold Air Induction System is so good, it even beats other aftermarket systems by up to 5 hp! This SLP 100% synthetic advanced filtration system tackles the job with its reusable filter construction that "out-flows" the competition, while it captures the most miniscule dust particles. The assembly also includes a unique Flow Indicator - a simple gauge that changes color when the filter needs to be cleaned. Simple bolt-on installation requires no modifications.