To complete this installation you will need to MODIFY the Original Equipment (O.E.) Mid-Pipe by expanding the outlets from to 2.25" to 2.5". This system upgrades your '84-'91 Corvette from the stock 2.25" diameter Axle-Back system to a more aggressive 2.5". The system features the classic S-Type sound with no drone inside the vehicle. It has dual BORLA® intercooled style 3.38" x 3" rectangle polished T-304 stainless steel tips on each muffler for a custom appearance. BORLA® Cat-Back™ & Axle-Back exhaust systems feature patented straight-through and multi-core technology to unleash hidden horsepower. Increased exhaust velocity adds power, driving excitement, fuel economy, and the distinctive BORLA® Sound of Power respected by motoring enthusiasts everywhere. Each system is built from premium, high-quality T-304 austenitic stainless steel, superior to T-400 series knockoffs (such as 409), to give you the absolute best in performance and durability. Ultra-smooth mandrel bends ensure maximum flow & power, and precision computer numerical control (CNC) manufacturing ensures an accurate fit. Best of all, BORLA® stands behind every system with a Million-Mile Warranty. Just what you'd expect from the world's most experienced (and most winning) exhaust brand.