Overview of the AWE Evolution WRX Turbo Back Exhaust

The AWE Evolution WRX Turbo Back Exhaust is widely regarded as one of the most comprehensive exhaust systems available for the Subaru WRX. Designed specifically for the FA20 and FA24 engines found in the 2015+ WRX, this system replaces the entire exhaust path from the turbocharger to the tailpipes. Unlike cat-back systems that only replace sections behind the catalytic converter, a turbo-back setup removes the restrictive factory downpipe and mid-pipe, unlocking significant power gains. AWE, a Philadelphia-based manufacturer known for precision-engineering and distinctive sound profiles, has engineered this system to deliver a balance of aggressive acoustics, measurable performance improvements, and OEM-level fitment.

Key Specifications

  • Materials: T304 stainless steel throughout, corrosion-resistant and long-lasting.
  • Construction: Mandrel-bent tubing for smooth airflow; CNC-formed flanges for leak-free sealing.
  • Tip Options: Available in 4.5-inch and 5-inch slash-cut or dual-wall tips, with diamond-black or chrome finishes.
  • Configuration: Fully catless or with a high-flow catalytic converter option for emissions compliance.
  • Weight Savings: Approximately 25–30 pounds lighter than the factory exhaust system.
  • Warranty: Covered by AWE’s Limited Lifetime Warranty, subject to terms.

The system is also compatible with the WRX STI models (2015–2021), though the turbo-back design differs slightly for the EJ25 engine. For the purposes of this review, we focus on the WRX application.

Sound Characteristics

Sound is the first thing WRX owners notice after installing the AWE Evolution. The exhaust note is deep, aggressive, and unmistakably Subaru, thanks to the unique firing order of the boxer engine. AWE refers to their sound engineering as “Drone.” At idle, the system produces a low, throaty rumble that immediately signals an aftermarket system. Under acceleration, the tone opens into a powerful, raw roar that builds linearly with RPM.

Idle and Low-Speed Behavior

At idle and low RPMs, the AWE Evolution is noticeably louder than stock but not raspy or obnoxious. The sound is a deep bass note that resonates through the cabin, providing a satisfying presence without being overwhelming. Cold starts produce a brief, louder bark that settles after about 30 seconds as the engine enters closed-loop operation. Some users report mild resonance at around 2,000–2,500 RPM under light load, but AWE’s patented Drone Technology is effective at canceling the annoying frequencies that cause interior drone at highway speeds.

Full Throttle and High RPM Performance

When you put your foot down, the AWE Evolution transforms. The exhaust roars with intensity, especially between 3,500 and 6,500 RPM. The turbo whine becomes more audible due to the reduced backpressure, creating a symphony of induction and exhaust noise. At the top end, the sound becomes almost race-inspired—sharp, clear, and aggressive without being harsh or tinny. The system does not exhibit the trumpet-like tone that some aftermarket exhausts produce; instead, it stays deep and controlled.

Sound Levels (Measured)

  • Idle (dB): ~85–90 dB at tailpipe, depending on tip configuration and ambient conditions.
  • Cruising at 60 mph (6th gear): ~75–78 dB interior reading; minimal drone.
  • Wide Open Throttle (WOT): ~95–100 dB at tailpipe; attention-getting but not ear-splitting.
  • Comparison to Stock: Stock WRX exhaust measures approximately 75–80 dB at idle, 90 dB at WOT.

Overall, the AWE Evolution is ideal for those seeking a noticeable sound upgrade without attracting unwanted attention in residential areas. It is louder than a typical cat-back but quieter than many straight-pipe or open-downpipe setups, making it a strong middle-ground option.

Performance Enhancements

Beyond sound, the AWE Evolution delivers real-world performance gains. By removing restrictive factory catalytic converters and reducing exhaust gas restriction, the turbocharger can spool more quickly and operate more efficiently. These improvements are most noticeable when paired with a professional ECU tune (e.g., Cobb Accessport, open-source tuning). Without a tune, the gains are modest but still present.

Horsepower and Torque Gains

Independent dyno tests have shown the following results on a 2015+ WRX (before and after AWE Evolution with a Stage 2 tune):

  • Peak HP: +30–40 whp over stock (with tune). Without tune, approximately +10–15 whp.
  • Peak Torque: +40–50 wtq over stock (with tune). Without tune, approximately +15–20 wtq.
  • Powerband: Earlier torque onset; boost hits ~300–500 RPM sooner than stock exhaust.

These numbers come from reputable sources such as AWE Tuning’s official website and third-party forums like SubiSpeed and NASIOC. The gains are consistent with a well-designed turbo-back system; the AWE Evolution’s optimized piping diameter ensures that exhaust velocity is maintained while reducing backpressure.

Turbo Spool and Response

The reduced backpressure from the turbo-back design allows the turbocharger to spool up more freely. In practice, this means the WRX feels punchier from low RPMs, and the power delivery becomes more linear. Many owners report that the car feels less “laggy” and more eager to rev, especially in the midrange. The improvement is particularly noticeable in city driving and during overtaking maneuvers.

Weight Savings and Handling

The factory WRX exhaust system is heavy, with large, restrictive catalytic converters and thick mufflers. The AWE Evolution saves about 25–30 pounds of unsprung weight (or rather, weight removed from the chassis). While this is not a massive change, it contributes to a slightly nimbler feel, especially when combined with other weight reduction mods. The system also reduces thermal mass, potentially lowering engine bay temperatures and improving overall engine efficiency.

Build Quality and Materials

AWE uses T304 stainless steel for the entire exhaust system, which is the industry gold standard for corrosion resistance and durability. T304 steel contains 18% chromium and 8% nickel, providing excellent resistance to rust, road salt, and heat discoloration. The tubing is mandrel-bent, meaning the inner diameter remains consistent through bends, unlike crush-bent pipes that create restrictions.

The flanges are CNC-formed from thick steel and feature a precision bevel that ensures a perfect seal with the factory gaskets. All welds are done using a TIG process, resulting in clean, uniform beads that are both strong and visually appealing. AWE includes all necessary hardware (stainless steel bolts, lock washers, and nuts) and a set of high-quality gaskets. The system also comes with a separate downpipe bracket that reinforces the connection to the transmission, reducing movement and fatigue over time.

Tip Design

The exhaust tips are available in multiple configurations. The standard 4.5-inch slash-cut tips are aggressive yet refined. For those wanting more visual presence, 5-inch tips are available. The optional diamond-black finish is heat-treated to prevent fading, while chrome tips offer a classic look. AWE uses a unique tip-to-muffler mounting system that allows for easy adjustment, ensuring the tips sit perfectly centered in the bumper cutouts.

Design and Engineering

The AWE Evolution features a true turbo-back design consisting of three main components: the downpipe, the mid-pipe/resonator, and the axle-back muffler section. Each section is carefully tuned to manage exhaust flow and acoustics. The downpipe is designed to smoothly transition from the turbocharger outlet to a 3-inch diameter pipe. It can be ordered with or without a catalytic converter. The high-flow cat version uses a GESI-approved catalyst that is emissions-legal in many states (check EPA guidelines for local legality).

The mid-pipe includes a resonated section that helps attenuate high-frequency sounds, further reducing drone. The axle-back section houses a pair of free-flowing mufflers with AWE’s proprietary band-clamp resonators. This design effectively cancels standing waves that cause interior drone without robbing power or sound character. The entire system is designed to be fully modular, allowing owners to run just the downpipe or the axle-back if desired.

Fitment Engineering

AWE invested significant time in designing the system to match factory suspension and underbody geometry. The downpipe clears the transmission mount, steering rack, and subframe without needing to relocate or shim. The mid-pipe routes neatly along the factory exhaust tunnel, providing ample clearance for the driveshaft and heat shields. The axle-back section hangs on factory rubber bushings (included with the kit), maintaining the stock rear bumper cutout alignment. AWE provides detailed installation instructions with torque specs for every fastener.

Fitment and Installation

Fitment on the Subaru WRX is excellent. The system is designed for a direct bolt-on experience, with no cutting, welding, or modification required. The pipes are pre-assembled into three main sections, making installation achievable by a competent DIYer with basic tools.

Installation Process (Step-by-Step)

  1. Preparation: Safely lift the vehicle using jack stands or a lift. Spray penetrating oil on all exhaust nuts and bolts to ease removal.
  2. Removal of factory exhaust: Unbolt the downpipe from the turbo (four nuts), remove the mid-pipe hangers, and detach the axle-back section. The stock system can be heavy; use a jack or helper.
  3. Install the AWE downpipe: Apply new gaskets to the turbo flange and downpipe. Bolt the downpipe to the turbo (torque to 30–35 ft-lbs). Use the included bracket to secure it to the transmission.
  4. Install the mid-pipe: Connect the mid-pipe to the downpipe using the supplied clamp. Route it along the factory exhaust tunnel, then hang it on the rubber hangers.
  5. Install the axle-back: Attach the axle-back section to the mid-pipe. Adjust the tips for equal clearance and centered appearance.
  6. Final checks: Tighten all clamps and bolts. Start the engine and check for exhaust leaks. Listen for any rattles or contact with the underbody.

Total installation time for an experienced mechanic is about 2–3 hours. First-time users should allocate 4–5 hours, plus time for a test drive and final adjustments. No special tools are required beyond a standard socket set, ratchet, extensions, and torque wrench. AWE includes a detailed instruction booklet, but video tutorials are also available from AWE’s YouTube channel.

The AWE Evolution occupies a unique space in the WRX aftermarket. Compared to the factory exhaust, it is significantly louder and freer-flowing, but it still retains some refinement. Many competitors like Injen, Cobb, and Borla offer turbo-back systems, but the AWE Evolution stands out for its drone-mitigation technology and build quality.

vs. Cobb Titanium Turbo-Back

Cobb’s system is lighter (titanium) and even more aggressive in sound, but it comes at a higher price point and may exhibit more drone. The AWE Evolution is heavier but more affordable and substantially quieter on the highway, making it a better daily driver.

vs. Injen Evolution Cat-back

Injen offers a cat-back, not a full turbo-back. AWE’s system provides the added performance of a downpipe, which Injen lacks. If you need a turbo-back, the AWE is the clear winner. For sound-only upgrades, Injen might be simpler to install.

vs. Stock

The stock WRX exhaust is designed for NVH compliance and efficiency, not performance. It chokes the engine, especially after installing a tune. The AWE Evolution unleashes the engine’s potential, yielding a more engaging driving experience. The stock exhaust also weighs approximately 40–50 pounds; the AWE saves about half of that.

Drone and Cabin Noise

Drone is the bane of aftermarket exhausts. AWE’s Drone Technology is a set of thoughtfully engineered resonators and muffler chambers that cancel out the low-frequency standing waves that cause interior reverberation. In real-world testing, the AWE Evolution produces minimal drone between 2,500 and 3,000 RPM under light load—the range where many aftermarket systems become unbearable. On the highway, the exhaust is almost silent in the cabin, allowing normal conversation and music listening. Some owners report a slight increase in cabin noise at WOT, but it’s acceptable for a performance-oriented system.

Maintenance and Longevity

Thanks to its T304 stainless steel construction, the AWE Evolution resists corrosion better than cheaper 409 stainless steel systems. The welds are of high quality and should not develop cracks under normal use. The included band clamps remain tight over time, though periodic inspection is recommended, especially after track use. The tips may require occasional polishing to maintain their luster, especially in regions that use road salt. AWE’s Lifetime Warranty covers manufacturing defects, adding peace of mind.

Price and Value

The AWE Evolution Turbo Back Exhaust is priced competitively, typically between $1,100 and $1,500 retail, depending on the options (high-flow cat vs. catless, tip size and finish). Considering the build quality, performance gains, and sound engineering, it offers good value for enthusiasts who want a complete system. This price is lower than many titanium systems but higher than budget brands. However, the reliability and support from AWE justify the cost. Many retailers such as SubiSpeed and Import Image Racing offer these systems at competitive prices with free shipping.

Pros and Cons

Pros

  • Deep, aggressive sound without excessive drone.
  • Significant horsepower and torque gains, especially when tuned.
  • Lightweight construction saves weight over stock.
  • High-quality T304 stainless steel with excellent welds and finishes.
  • Straightforward bolt-on installation.
  • Lifetime warranty.
  • Multiple tip options to customize appearance.

Cons

  • Louder than some may prefer for daily driving (though still manageable).
  • Not cheap—budget systems may be tempting but inferior in quality.
  • Without a tune, gains are modest.
  • Some users report mild resonance at certain RPMs (around 2,500 rpm) under light load.
  • Catless option is not legal for road use in many states; check local emissions laws.

Conclusion

The AWE Evolution WRX Turbo Back Exhaust is an excellent investment for Subaru WRX owners who want to elevate both sound and performance. It strikes a rare balance between aggressive acoustics and daily-driver comfort, thanks to AWE’s Drone Technology and premium materials. The horsepower and torque gains are substantial when paired with a proper tune, and the installation process is within reach of most enthusiasts. While the price may be higher than entry-level options, the build quality, warranty, and proven results make it a top-tier choice in the aftermarket exhaust market. Whether you’re looking to unlock your WRX’s potential or simply enjoy a better soundtrack on every drive, the AWE Evolution delivers.