HKS 31021-BF001 Legamax Premium Catback Exhaust for 2015-21 Subaru WRX/STI AWD

Vehicle Fitment

• 2015-2021 Subaru WRX & Subaru WRX STI (VA-Series AWD)

Features

• HKS Legamax Premium cat-back exhaust system engineered for Subaru WRX/STI
• Smooth mandrel-bent piping for improved exhaust flow and reduced backpressure
• Quad 90 mm polished stainless tips with HKS branding for aggressive look
• SUS304 stainless steel main construction for long-lasting corrosion resistance
• 75 mm center pipe splitting to dual 69 mm branches ahead of mufflers
• Fine-tuned muffler design balances sporty sound without harsh drone
• Direct bolt-on fitment using OEM hangers and included gaskets/hardware
• Enhances throttle response and peak power delivery throughout the powerband

Specifications

• Main pipe diameter: 75 mm → dual 69 mm
• Quad tip diameter: 90 mm (left & right)
• Main material: SUS304 stainless steel
• Fitment: AWD chassis only (WRX & WRX STI)
• Weight: approx. 35 lb (15.9 kg) full assembly
• Noise level: approx. 83 dB at idle (varies by vehicle and conditions) :contentReference[oaicite:0]{index=0}
• Direct bolt-on - no cutting, welding, or modification required :contentReference[oaicite:1]{index=1}

Included Components

• 1x Cat-back exhaust assembly
• 1x Set of gaskets for stock connection
• 1x Set of mounting hardware (bolts, nuts, washers)
• 4x Polished quad tips installed
• Installation instructions

Product Description

The HKS 31021-BF001 Legamax Premium Catback Exhaust is a high-quality performance exhaust system specifically designed for Subaru WRX and WRX STI models built from 2015 through 2021. Constructed from durable SUS304 stainless steel, this cat-back system replaces the restrictive factory exhaust from the catalytic converter back, allowing exhaust gases to flow more freely for improved throttle response and power gains. With mandrel-bent piping and a tailored muffler design, it produces a sportier yet refined exhaust note without excessive drone at cruising speeds.

The quad 90 mm polished tips provide an aggressive rear aesthetic, while the system's direct bolt-on design utilizes OEM hangers and includes all necessary gaskets and hardware for installation. Designed for AWD Subaru platforms, this exhaust enhances the driving experience by reducing backpressure and broadening the powerband across the RPM range - making it an excellent upgrade for enthusiasts seeking both performance and daily usability.