w/ SPT midpipe Axle Back 3.5" Single Wall Neochrome Tips and No Muffler

• 2015–2021 Subaru | WRX STI
• 2015–2021 Subaru | WRX

Designed specifically to replace the factory STI Performance (SPT) axleback section

After countless requests from customers seeking an upgrade to the STI Performance / SPT Exhaust, we decided to bring one in for testing. The results confirmed what many enthusiasts already knew: the factory SPT system leaves a lot to be desired.

While nearly silent at idle and low RPM, the SPT exhaust produces a persistent drone during cruising speeds—exactly when you'd want quiet—and then practically disappears above 5000 RPM, providing none of the rewarding sound you'd expect at wide open throttle.

We knew we could do better.

Product Features

• Direct Bolt-On for SPT Midpipe – 100% compatible with the STI Performance (SPT) midpipe

• No Drone, Better Tone – Deep and refined sound at idle and cruise with an aggressive tone at WOT

• Mandrel-Bent T304 Stainless Tubing – Built for flow, strength, and corrosion resistance

• Fully TIG Welded – Precision craftsmanship throughout

• Factory Fit Flanges and Hangers – Bolts right in, no modifications required

• 23.3lbs Weight Reduction – Drops serious weight vs. the factory muffler box

• Made in the USA – Fabricated in-house at our facility in Woodland, WA

Why This Axleback?

This muffler delete replaces the baffled factory rear section with a free-flowing, performance-tuned axleback that eliminates the drone from the SPT system while providing the rich, full-bodied tone enthusiasts want. It transforms daily driving with more feedback, more excitement, and better response across the powerband.

Typical gains from this upgrade:

• +6–8 ft-lb torque on WRX

• +8–12 ft-lb torque on STI

Tip Style: 3.5" Single Wall Neochrome

• Larger than stock, but clean and proportional

• 3.5” diameter with polished blue-flame finish

• Slash-cut with a performance-inspired look

Installation Notes

Installation is straightforward with basic hand tools:

• Remove six factory bolts and four exhaust hanger bushings

• Mount the new axleback using factory hangers

• Use included hardware and gaskets to seal the connection

• Align the tips in the valence cutouts and torque to ~20 ft-lb

Whether you're chasing performance, better sound, or simply trying to eliminate that annoying midrange drone, this axleback delivers. Affordable, lightweight, and built to last—this is the upgrade the STI Performance exhaust should have been from the start.

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