What Is a Turbo Back Exhaust and Why Upgrade?

A turbo back exhaust replaces every exhaust component from the turbocharger’s outlet to the tailpipe. On a Subaru WRX, this typically includes the downpipe, midpipe (or intermediate pipe), and the catback section. Unlike a simple axle-back or catback system, a turbo back setup removes the restrictive factory downpipe and catalytic converters, allowing exhaust gases to exit the engine far more quickly. This reduction in backpressure lets the turbocharger spool up faster, reduces exhaust gas temperatures, and unlocks significant horsepower and torque gains, often in the range of 20–40 whp on a properly tuned WRX.

However, upgrading to a turbo back exhaust is not a simple bolt‑on affair. Because you are removing or replacing the catalytic converters, the vehicle’s oxygen sensors will detect changed exhaust flow, which can trigger a check engine light or cause the ECU to run in a limp‑mode fuel map. For best results, a professional ECU tune (via AccessPort, Ecutek, or OpenECU) is highly recommended. This ensures the air‑fuel ratios are optimized for the new exhaust flow and that any check‑engine lights are properly addressed.

When shopping for a turbo back exhaust under $1,000, you’ll find systems made from stainless steel (often T‑304 grade), with either a high‑flow catalytic converter or a catless downpipe. Many of these kits are designed for a direct bolt‑on fitment on 2015–2021 WRX models, though some also support older GD/GH/GR chassis. Below we dive into the five best options that combine performance, sound, and value without breaking the bank.

1. Invidia Q300 Turbo Back Exhaust

The Invidia Q300 has long been a favorite among WRX owners who want a pronounced, aggressive exhaust note without drone at highway speeds. This system is crafted from T‑304 stainless steel with mandrel‑bent tubing and a polished finish that resists corrosion. The straight‑through design uses a Helmholtz resonator and a large, multi‑chamber muffler to cancel out unwanted frequencies while still letting the boxer engine’s rumble shine through.

Key Specs

  • Material: 304 stainless steel, 3‑inch diameter
  • Sound Character: Deep, aggressive at WOT; mild and refined during cruising
  • Fitment: Direct bolt‑on for 2015–2021 WRX; includes all necessary gaskets and hardware
  • Downpipe Options: Available with catted or catless downpipe
  • Price: Around $950–$1,100 (typically under $1,000 for the catless version)

Performance and Sound

On the dyno, the Q300 turbo back (with a proper tune) consistently adds 25–30 whp and 20–25 lb‑ft of torque on a 93‑octane tune. The sound is well‑balanced: it’s loud enough to turn heads when you get on it, but quiet enough for daily commuting thanks to the integrated resonator. The Q300 also pairs extremely well with an aftermarket intake and an AccessPort tune, making it a popular starting point for stage 2 builds.

Pros and Cons

  • Pros: Excellent build quality; no drone; great fitment; retains the classic WRX burble
  • Cons: The polished finish requires periodic cleaning to avoid spotting; some users report the muffler tip sticks out slightly past the bumper

View the Invidia Q300 on Invidia’s official site

2. Cobb Tuning Turbo Back Exhaust

Cobb Tuning is synonymous with Subaru performance. Their turbo back exhaust system is engineered from the ground up to work seamlessly with the AccessPort and Cobb’s Off‑the‑Shelf (OTS) tunes. The kit includes a high‑flow catalytic converter in the downpipe, a resonated intermediate pipe, and a straight‑through muffler that produces a deep, refined tone without excessive noise.

Key Specs

  • Material: T‑304 stainless steel, 3‑inch diameter
  • Sound Character: Deep and aggressive, but very linear; minimal drone
  • Fitment: Direct replacement; includes hardware and pre‑installed O2 sensor bungs
  • Downpipe: Catted (high‑flow 200‑cell metallic substrate)
  • Price: Usually $999–$1,050; often found slightly under $1,000 on sale

Performance and Sound

With the Cobb Stage 2 tuning package (AccessPort + turbo back), owners report gains of up to 35 whp and 30 lb‑ft of torque on 91‑octane fuel. The sound is aggressive but not obnoxious; it has that signature Subaru boxer rumble with a crisp, clean note. Cobb’s attention to resonance tuning means you can hold highway speeds without being fatigued by drone. The catted downpipe also helps keep emissions legal in many states and reduces the smell of raw fuel that catless setups sometimes produce.

Pros and Cons

  • Pros: Perfectly tuned for Cobb OTS maps; high‑flow cat retains street legality; amazing build quality; comes with a lifetime warranty
  • Cons: Pricier than some competitors; catless version not available directly from Cobb (you’d have to source separately); fitment can be tight on older WRX models

See the Cobb Tuning turbo back on Cobb’s website

3. Borla Turbo Back Exhaust

Borla has been a giant in the aftermarket exhaust world for decades, and their WRX turbo back system continues that legacy. Built from aircraft‑grade T‑304 stainless steel with a unique “straight‑through race core” muffler design, the Borla exhaust produces a distinctive, aggressive tone that sets it apart from the competition. The system is engineered for maximum flow without compromising low‑end torque.

Key Specs

  • Material: T‑304 stainless steel, 3‑inch diameter
  • Sound Character: Distinctive, deeper than stock with a sharp, aggressive edge
  • Fitment: Direct bolt‑on; comes with all gaskets, hardware, and a polished stainless tip
  • Downpipe Options: Catted (with a robust metallic substrate) or catless
  • Price: $950–$1,050 (catted version usually under $1,000)

Performance and Sound

The Borla system is all about maximizing exhaust velocity. On a stage 2 tune, expect gains similar to the Invidia and Cobb offerings—around 25–30 whp. Where Borla shines is sound. The “Borla sound” is legendary, with a crackle and pop on deceleration that many enthusiasts love. The drone is well controlled, though the catless version can be boomy at certain RPMs. The catted variant retains a clean tone and passes visual inspections in most areas.

Pros and Cons

  • Pros: Legendary sound and fitment; high‑quality welds; lifetime warranty
  • Cons: The catless downpipe can throw a CEL without a tune; some consider it too loud for daily use; price near the $1,000 ceiling

Explore Borla’s WRX turbo back options

4. Nameless Performance Turbo Back Exhaust

Nameless Performance came onto the scene with a focus on providing affordable, high‑quality exhausts for the Subaru community. Their turbo back system for the WRX is a true budget‑friendly option that does not sacrifice sound or construction. It uses T‑304 stainless steel, mandrel bends, and a straight‑through design. Nameless offers both a “muffler delete” catback section and a resonated midpipe to let customers tailor the volume.

Key Specs

  • Material: 304 stainless steel, 3‑inch diameter
  • Sound Character: Deep, aggressive; can be very loud with muffler delete option
  • Fitment: Direct bolt‑on; supplied with V‑band clamps and gaskets
  • Downpipe: Catted (high‑flow catalytic converter) or catless
  • Price: $850–$950 (depending on configuration)

Performance and Sound

Nameless focuses on flow. A catless downpipe paired with their straight‑through muffler delete produces one of the loudest, most raw sounds you can get for under $1,000. With a tune, power gains mirror the other options. The resonated version adds a Helmholtz chamber to cancel drone, making it more livable for daily driving. For the money, it’s hard to beat the value: you get a full turbo back, quality materials, and a sound that can be customized to your tolerance.

Pros and Cons

  • Pros: Very affordable; great sound with customizability; excellent customer service; made in the USA
  • Cons: The muffler delete option can be ear‑splittingly loud; welds are not as polished as Cobb or Borla; downpipe may require a slight modification for perfect fitment on some model years

Learn more on Nameless Performance’s site

5. HKS Legamax Premium Turbo Back Exhaust

HKS is a Japanese aftermarket giant with a sterling reputation for precision engineering. The Legamax Premium turbo back exhaust is designed to offer a refined, luxurious sound while still delivering substantial performance gains. It uses a unique “advanced exhaust flow” layout that minimizes turbulence and maximizes flow velocity. The Legamax is often praised for its smooth, deep tone that never sounds raspy or tinny.

Key Specs

  • Material: T‑304 stainless steel, 3‑inch diameter
  • Sound Character: Smooth and aggressive; deeper than stock with a refined, exotic note
  • Fitment: Direct bolt‑on for 2015–2021 WRX; includes all mounting hardware and gaskets
  • Downpipe: Catted (high‑flow metal matrix) or catless
  • Price: $960–$1,040 (usually found slightly under $1,000 for the catless version)

Performance and Sound

The HKS Legamax is a bit different from the competition. Instead of just a straight‑through tube, HKS uses an internal resonator structure that creates a more balanced exhaust pulse. The result is a sound that is aggressive when you floor it but nearly stock‑like at idle. Dyno tests show gains of around 25 whp on a tune, with excellent low‑end torque response. The build quality is top‑notch, with polished tips and precise welds.

Pros and Cons

  • Pros: Extremely refined sound; excellent fitment; premium materials; good for daily drivers who want a sporty but not obnoxious note
  • Cons: On the higher end of the budget; the muffler section is quite large, which can be a visual downside for some; not as loud as the Nameless or Invidia Q300

View the HKS Legamax on HKS’s website

What to Consider Before Buying

Before pulling the trigger on a turbo back exhaust, factor in these key points:

  • Emissions: Catless downpipes will not pass a visual inspection in many states and may increase exhaust smell. A catted downpipe with a high‑flow converter is a better choice for street‑driven cars.
  • Need for a Tune: All of these exhausts will dramatically alter your air‑fuel ratio. Without a tune, you risk running lean, which can lead to engine knock or damage. Plan to budget for an AccessPort or a professional ECU reflash.
  • Drone: Look for systems that include a resonator or Helmholtz chamber if you do a lot of highway driving. The Cobb and Invidia Q300 are the quietest inside the cabin; the Nameless muffler delete is the loudest.
  • Fitment: Most modern turbo back kits are direct fit for 2015–2021 WRXs, but older chassis (2008–2014) may require different downpipe flanges. Always double‑check compatibility with your exact model year and trim.
  • Installation Difficulty: A turbo back swap is moderately difficult. Expect 2–4 hours with basic hand tools, ramps, and penetrating oil for stubborn bolts. New gaskets and hardware are usually included, but it’s wise to have a second set of hands.

Which One Should You Choose?

If you want a balanced daily driver: the Invidia Q300 or Cobb Tuning turbo back are excellent choices. They offer refined sound, no drone, and proven power gains with Cobb OTS tunes.

If you prioritize an iconic exhaust note: the Borla is hard to beat. Its distinct crackle and pop make it a favorite among enthusiasts who enjoy a raw, aggressive sound.

For the budget‑conscious: the Nameless Performance system delivers the most bang for the buck, especially if you don’t mind a louder exhaust.

For a refined, luxury‑sports‑car sound: the HKS Legamax Premium is a fantastic option that will turn heads without annoying your neighbors.

No matter which one you go with, pairing your turbo back exhaust with a solid tune will transform your WRX from a capable daily driver into a genuinely exhilarating performance machine. Each of these systems is under $1,000, so you can upgrade your sound and power without draining your wallet.

Frequently Asked Questions

Will a turbo back exhaust void my warranty?

Replacing the exhaust system itself does not automatically void your entire warranty, but if a component failure can be linked to the aftermarket exhaust (e.g., an engine knock caused by running lean without a tune), the dealer may deny coverage. Installing a tune will almost certainly void the powertrain warranty.

Do I need a tune after installing a turbo back?

Yes. The increased exhaust flow will cause the engine to run lean. A tune—via AccessPort, Ecutek, or custom map—is required to keep air‑fuel ratios safe and to prevent check engine lights. All manufacturers strongly recommend tuning immediately after installation.

How much horsepower can I expect?

With a proper stage 2 tune, a turbo back exhaust on a 2015–2021 WRX typically adds 25–35 whp and 20–30 lb‑ft of torque. Gains vary depending on fuel quality, altitude, and the specific downpipe design (catted vs. catless).

In most states, it is illegal to remove or replace a functioning catalytic converter with a test pipe or catless downpipe. Check your local emissions laws before purchasing. A high‑flow catted downpipe is street legal in many areas and still offers excellent performance.

Can I install a turbo back exhaust myself?

If you have basic mechanical skills, a socket set, ramps or jack stands, and some patience, yes. The most challenging part is often removing the old downpipe hardware, which can rust. Use penetrating spray and new gaskets to ease the process. Expect about 2–4 hours of work.