HKS Hi-Power Cat Back Exhaust Single Exit Subaru WRX / STI 2015-2021 | 31006-BF003

The HKS Hi-Power Cat-Back Exhaust System is a premium performance upgrade engineered specifically for the 2015-2021 Subaru WRX and WRX STI. Designed and manufactured by HKS — one of Japan's most respected performance tuning brands — this single-exit muffler system delivers a refined, aggressive exhaust note while improving exhaust flow over the restrictive factory system. Whether you're building a track-ready STI or simply want a more exhilarating daily-driver WRX, the Hi-Power series strikes the ideal balance between performance gains and street-friendly sound levels.

Key Features & Benefits

• Optimized Exhaust Flow — Mandrel-bent piping minimizes restriction and turbulence for improved scavenging and potential horsepower gains across the RPM range.
• Signature HKS Hi-Power Sound — Engineered muffler internals produce a deep, sporty exhaust tone that is aggressive under acceleration without being excessively loud at idle or cruising speeds.
• Premium Stainless Steel Construction — Built from high-grade stainless steel for superior corrosion resistance, long-term durability, and a polished appearance that holds up to daily driving and track use.
• Single-Exit Configuration — Clean, sleek single-exit tip design complements the WRX/STI rear bumper fascia for a purposeful, OEM-plus aesthetic.
• Direct Bolt-On Fitment — Precision-engineered to match factory mounting points and flanges for a straightforward, no-modification installation on compatible 2015 WRX and WRX STI models.
• Reduced Exhaust Back Pressure — Improved exhaust gas evacuation supports turbocharger efficiency, helping the EJ/FA powerplant breathe more freely under boost.
• HKS Quality Assurance — Every component is manufactured to exacting HKS standards and undergoes rigorous quality control, a brand with decades of proven motorsport heritage.

What's Included

• HKS Hi-Power Cat-Back Muffler / Exhaust Section (Single Exit)
• Polished Stainless Steel Exhaust Tip
• OEM-Style Mounting Hardware & Gaskets
• Rubber Exhaust Hangers
• HKS Installation Instructions

Specifications