Invidia HS15SW4G3S Q300 Single Exit Cat-Back for 15-21 Subaru WRX/STI

Vehicle Fitment

• 2015-2021 Subaru WRX & WRX STI (4-door sedan, 2.0L & 2.5L Turbo, AWD)

Features

• Q300 single exit cat-back exhaust system tuned for balanced flow
• Mandrel-bent 76 mm stainless steel piping for optimized exhaust flow
• Flat-bottom muffler design for reduced high-speed drag
• Polished single rolled stainless steel tip for refined look
• Improved throttle response and torque gains over stock exhaust
• Deep, sporty exhaust tone without excessive drone
• CNC-machined flanges and robot TIG-welded construction for durability
• Direct bolt-on installation with factory hangers and hardware

Specifications

• Part number: HS15SW4G3S
• Main piping diameter: ~76 mm (3")
• Tip diameter: ~110 mm single rolled stainless steel
• Material: SUS304 polished stainless steel
• Exit configuration: Single right-side outlet
• Muffler style: Q300 tuned design

Included Components

• 1x Invidia Q300 single exit cat-back exhaust system (HS15SW4G3S)
• 1x Polished stainless steel exhaust tip
• Installation hardware (clamps, gaskets, brackets)

Product Description

The Invidia HS15SW4G3S Q300 Single Exit Cat-Back Exhaust System is a premium aftermarket upgrade specifically designed for 2015-2021 Subaru WRX and WRX STI sedans. Featuring mandrel-bent 76 mm stainless steel piping and a flat-bottom muffler design, this exhaust enhances exhaust gas flow over the stock system, helping increase throttle response and torque while delivering a rich, deep tone with moderate sound levels. The polished single rolled stainless steel tip adds a refined visual upgrade at the rear of the vehicle.

Constructed with high-quality SUS304 stainless steel and precision TIG-welded joints, this direct bolt-on cat-back exhaust installs easily using the vehicle's existing hangers and mounting points. Whether you're seeking improved performance, a better exhaust note, or a cleaner rear-end aesthetic for your WRX/STI, the Q300 single exit system provides a balanced upgrade ideal for both street and weekend performance driving.