MBRP S4801304 Armor Pro 2.5in Axle-Back Exhaust for 2011-2021 Subaru WRX/WRX STI

Vehicle Fitment

• 2011-2014 Subaru Impreza WRX Sedan (2.5L Turbocharged H-4)
• 2011-2014 Subaru Impreza WRX STI Sedan (2.5L Turbocharged H-4)
• 2015-2021 Subaru WRX (Base, Premium, Limited; 2.0L Turbocharged H-4, FWD/AWD)
• 2015-2021 Subaru WRX STI (Base, Premium, Limited, Sport; 2.5L Turbocharged H-4, AWD)

Fitment Notes

• 2011-2014 fitment is for the Sedan body style only - does not fit the 2011-2014 Impreza hatchback due to different exhaust routing and rear bumper configuration
• 2015-2021 WRX is compatible with the 2.0L engine only; 2015-2021 WRX STI is compatible with the 2.5L engine only
• No-muffler (muffler delete) design - replaces the factory muffler section; no replacement muffler is included by design

Features

• Street Profile sound tuning produces a deeper, more aggressive exhaust note under throttle while maintaining a composed, non-droning character at highway cruise speeds
• Quad rear exit configuration delivers an aggressive, symmetrical four-tip appearance at the rear bumper - one of the most visually distinctive exit styles available for the WRX/STI platform
• T304 stainless steel construction - MBRP's highest-grade material - resists rust, corrosion, and degradation in extreme cold-weather, snow, and road-salt environments
• Mandrel-bent 2.5-inch tubing eliminates rippling in bends to maximize exhaust flow velocity and reduce backpressure compared to the factory system
• Muffler-delete (no-muffler) design removes the restrictive factory muffler to further improve exhaust gas flow and deliver a more unfiltered boxer engine sound signature
• Includes dual 3.5-inch OD mirror-polished T304 stainless steel single-wall angle-cut tips for a clean, performance-oriented finish
• Direct bolt-on installation using factory OEM hanger locations - no cutting, welding, or drilling required
• Welded-on hanger brackets ensure a secure, rattle-free fit to the factory undercarriage mounting points
• Backed by MBRP's Lifetime Warranty as part of the Armor Pro series - MBRP's top-tier durability designation

Specifications

• Part Number: S4801304
• Exhaust Type: Axle-Back
• Series: Armor Pro
• Sound Profile: Street Profile
• Exit Style: Quad Rear Exit
• Muffler: No Muffler (muffler delete)
• Tubing Diameter: 2.5 inches
• Tip Style: Single Wall, Angle Cut
• Tip Outlet Diameter: Dual 3.5-inch OD
• Tip Material: Mirror-polished T304 Stainless Steel
• Body Material: T304 Stainless Steel
• Hanger Style: Welded-on
• Fuel Type: Gasoline
• Drivetrain: AWD (WRX STI all years); AWD/FWD (WRX 2015-2021)
• Position: Rear axle-back (replaces factory muffler and rear pipe section from the axle rearward)
• Warranty: Lifetime (Armor Pro)

Included Components

• 1x Axle-back exhaust pipe assembly (T304 stainless steel, mandrel-bent 2.5-inch tubing, welded hangers)
• 2x T304 stainless steel single-wall angle-cut tips (3.5-inch OD, mirror-polished)
• 1x Hardware and installation kit (clamps and mounting hardware)
• 1x MBRP installation instructions

Product Description

The MBRP S4801304 is a 2.5-inch Armor Pro quad rear exit axle-back exhaust system purpose-built for the 2011-2014 Subaru Impreza WRX and WRX STI Sedan as well as the 2015-2021 Subaru WRX and WRX STI. As a muffler-delete axle-back design, this system removes the factory muffler entirely and replaces it with free-flowing, mandrel-bent T304 stainless steel tubing routed into four exhaust outlets at the rear bumper. The result is a more unfiltered expression of the Subaru boxer engine's signature character, paired with MBRP's Street Profile tuning that keeps the tone engaging under acceleration without becoming fatiguing during daily commutes or extended highway drives.

The quad rear exit layout is one of the most aggressive visual configurations available for this platform, giving the rear bumper a track-ready appearance with four mirror-polished 3.5-inch single-wall stainless steel tips. All tubing is constructed from T304 stainless steel - the highest chromium and nickel content of any exhaust-grade steel - making the S4801304 purpose-fit for WRX and STI owners in cold-climate, high-salt, or high-moisture environments where lesser materials would degrade quickly. Welded-on hanger brackets align precisely with the factory mounting locations for a clean, rattle-free installation without any modifications to the vehicle.

Installation is a straightforward bolt-on process using the factory OEM hanger points with no cutting, welding, or drilling required. Important fitment notes: the 2011-2014 Impreza compatibility is restricted to the Sedan body style only - the hatchback body uses different exhaust routing and is not supported by this system. The 2015-2021 WRX is supported with the 2.0L turbocharged engine, while the 2015-2021 WRX STI requires the 2.5L turbocharged engine. The S4801304 is covered by MBRP's Lifetime Warranty and represents the ideal axle-back upgrade for WRX and STI enthusiasts seeking a dramatic visual and auditory transformation with proven long-term durability.