The Custom Muffler BCO364 is a full stainless-steel exhaust system developed exclusively for competition use on the Subaru WRX S4.

Engineered for drivers who demand maximum sound presence and weight reduction for the track, this system delivers an aggressive, race-focused exhaust character and high-flow performance beyond street-legal constraints.

Product Highlights

⚠️ COMPETITION-ONLY PERFORMANCE DESIGN
This exhaust system is designed strictly for motorsports and off-road use. It is not compliant with public road regulations, allowing for unrestricted exhaust flow and a powerful, race-focused sound profile. Purchase requires completion of a designated competition product application form.

🔊 AGGRESSIVE COMPETITION SOUND OUTPUT
Delivers commanding exhaust volume suitable for circuit and closed-course driving:

• Nearby Exhaust Noise: 103 dB

• Idling Noise: 75 dB
  This setup provides raw, unfiltered auditory feedback and emphasizes the turbocharged FA24 engine’s character under full acceleration.

🔧 FULL SYSTEM FOR MAXIMUM PERFORMANCE
A complete 2-piece replacement system that removes significant weight from the rear. Designed as a direct fit for the CVT-equipped WRX S4, it replaces the entire factory exhaust from the center pipe back to optimize exhaust evacuation.

🏗️ ULTRA-LIGHTWEIGHT STAINLESS CONSTRUCTION
Manufactured entirely from stainless steel, the system prioritizes drastic weight reduction while maintaining durability:

• System Weight: 9.5 kg (OEM reference: 22.1 kg)

• Single right-side exit with a large 100mm tailpipe diameter

• Features an 80mm main pipe for high flow capacity.

Technical Specifications & Application

This is a competition-use, full stainless steel exhaust system for the Subaru WRX S4.

Key Details

• Product Name: Custom Muffler (For Competition Use Only)

• Product Code: BCO364

• JAN Code: 4512355225473

• Stock Status: In stock

Vehicle Compatibility
WRX S4

• Chassis: 5BA-VBH (Acceleration noise regulation applicable vehicle)

• Engine: 2.4L Turbo (FA24)

• Drivetrain: 4WD (AWD)

• Grade: GT-H, STI Sports R (including EX trim)

• Transmission: CVT

• Model Years: From November 2021

Construction & Dimensions

• Material: All Stainless Steel

• Pipe Diameter: 80 mm

• Tailpipe Diameter: 100 mm

• Exit Direction: Single, Right

• Number of Sections: 2

• Unit Weight: 9.5 kg

• Packaging Size: 1400 × 350 × 500 mm

This product is for competition use only and cannot be used on public roads.