SLP Performance

SLP Performance: Street Legal Power Since 1987

SLP Performance — short for Street Legal Performance — has been one of the most respected names in the American muscle car aftermarket since its founding in 1987. Based in Plymouth, Michigan, SLP built its reputation on a bold premise: that a performance upgrade could deliver real, measurable power gains while still passing emissions testing in all 50 states. That philosophy continues to define everything the brand produces today.

SLP exhaust system kits are perhaps the brand's most iconic product line. From the legendary LoudMouth series to axle-back and cat-back configurations, SLP exhaust systems are engineered specifically for late-model GM platforms like the Camaro and Firebird, as well as Mopar and Ford muscle cars. Each system is designed to unlock meaningful horsepower and torque gains while delivering a deep, aggressive exhaust note that muscle car enthusiasts demand — without crossing into obnoxious drone on the highway.

Complementing those full systems, SLP exhaust resonators offer a targeted solution for drivers who want to refine their exhaust tone or replace a worn factory resonator with a performance-oriented piece. SLP's resonator components are built to integrate seamlessly with their complete exhaust kits or to serve as a standalone upgrade for compatible factory exhaust setups.

On the induction side, SLP has long been a leader in cold air and ram-air technology. Their engine air box covers are engineered to work in concert with SLP's broader air intake systems, directing cooler, denser air into the engine for improved throttle response and horsepower output. These components are a natural starting point for any enthusiast looking to build on the gains delivered by an SLP exhaust upgrade.

Built for American Muscle

What has always set SLP apart is a commitment to integrated engineering. Rather than producing generic bolt-on parts, SLP's team of engineers designs products that work together as a system — exhaust, induction, and drivetrain components that are validated on in-house chassis and engine dynamometers before ever reaching a customer's garage. The result is a lineup that routinely exceeds OEM fit and finish standards while delivering aftermarket performance gains.

SLP's catalog centers on some of America's most beloved performance platforms: the Chevrolet Camaro, Pontiac Firebird, Dodge Challenger, Dodge Charger, and Ford Mustang. Whether you are restoring a classic F-body or modernizing a late-model pony car, SLP offers a focused, well-validated lineup of parts built for your specific application.