What Is a Midpipe and Why Upgrade?

In the exhaust system of a Subaru BRZ or Toyota 86, the midpipe is the section that connects the front pipe (or downpipe in turbocharged applications) to the rear axle-back or cat-back system. On the FA20-powered twins, the stock midpipe is designed primarily for noise suppression and emissions compliance, often with restrictive bends and small-diameter tubing. Replacing it with an aftermarket midpipe improves exhaust gas velocity, reduces backpressure, and can free up 5–10 horsepower when paired with other bolt-on modifications. Beyond power, the midpipe is the single most effective component for shaping the exhaust note, removing the factory muffling to deliver a sharper, more engaging sound without overwhelming drone if chosen wisely.

An upgraded midpipe also reduces weight. Stock units typically use heavy steel with bulky resonators, while aftermarket options use lighter stainless steel or titanium. This unsprung weight reduction improves suspension response and overall handling feel—a key benefit for a car that thrives on cornering agility. Combined with a quality cat-back system, a midpipe upgrade can transform the character of your BRZ or 86 from subdued to thrilling, while still remaining streetable.

Top Midpipe Options for Subaru BRZ and Toyota 86

The market offers numerous midpipe choices, each with distinct sound profiles, construction quality, and performance characteristics. Below are five standout options that have proven themselves in the enthusiast community. When evaluating them, consider your target exhaust note (aggressive vs. refined), whether you want to retain a catalytic converter or resonator for legal compliance, and your budget for a full cat-back or axle-back combination.

Invidia Q300 Midpipe

The Invidia Q300 midpipe is one of the most balanced options for daily-driven BRZ/86 builds. It is constructed from 3-inch T304 stainless steel mandrel bent tubing, which ensures optimal flow with minimal turbulence. The Q300 midpipe features a polished finish and a built-in resonator that effectively cancels out annoying drone frequencies while allowing the boxer engine’s signature burble to come through. This midpipe mates directly with Invidia’s Q300 cat-back exhaust but is also compatible with many other aftermarket cat-back systems using standard flanges.

Sound-wise, the Q300 provides a deep, aggressive tone under hard acceleration that settles into a civilized hum at cruising speeds. It is not the loudest option, making it a favorite among owners who want an audible improvement without attracting unwanted attention from law enforcement. Installation is straightforward with all necessary gaskets and hardware included. For those seeking a performance edge, the 3-inch diameter supports up to 400 horsepower, giving ample headroom for future forced induction upgrades. A notable downside is its price point, which sits at the upper end of the midpipe segment, but the quality and customer support justify the investment.

GReddy Midpipe

GReddy is a household name in Japanese performance tuning, and their midpipe for the BRZ/86 reflects decades of motorsport experience. The GReddy midpipe uses 2.5-inch diameter piping from high-quality SUS304 stainless steel, paired with a free-flowing resonator that maintains a refined yet sporty exhaust note. GReddy engineers designed this midpipe to be a direct bolt-in replacement that does not require any modifications to the factory hangers or mounting points.

The key advantage of the GReddy midpipe is its flow-optimized design, which reduces exhaust gas temperature and improves spool time when paired with a turbocharger—although naturally aspirated builds also benefit from a smoother torque curve. The sound character is controlled with a mild roar that builds as revs climb, without the raspiness that affects some budget midpipes. GReddy backs their product with a limited lifetime warranty, instilling confidence in its durability. However, the 2.5-inch diameter may become a bottleneck for heavily modified cars targeting over 300 horsepower, so serious builders should consider stepping up to a 3-inch unit.

ARK Performance Midpipe

ARK Performance is known for precision-crafted exhaust systems that deliver a distinguished exhaust note. Their midpipe for the Subaru BRZ and Toyota 86 is part of the GRiP series, featuring 3-inch T304 stainless steel construction and a hand-welded resonator that produces a deep, throaty tone without excessive drone. ARK uses a polished mirror finish that stands out under the car, and they include CNC-machined flanges with laser-cut gaskets for a perfect seal.

What sets ARK apart is the attention to sound engineering. Their patented resonance tuning chamber minimizes unwanted frequencies in the mid-range, meaning you get a sporty exhaust note when you step on it, but a quiet cabin during highway cruising. This makes the ARK midpipe an excellent choice for driver who want performance without sacrificing daily comfort. It installs easily and is compatible with most aftermarket cat-back systems. The only drawback is the premium pricing, but for owners who prioritize sound quality and build precision, ARK is hard to beat.

Agency Power Midpipe

Agency Power offers a midpipe that balances value and performance. Constructed from T304 stainless steel with a 2.75-inch diameter, it offers a good compromise between the 2.5-inch factory sizing and a full 3-inch race pipe. The midpipe comes with a high-flow resonator that reduces rasp while still allowing a noticeable increase in exhaust volume. Agency Power uses robotic TIG welding for consistent, strong joints, and the midpipe includes a pair of flanges with factory-style bolt holes for a hassle-free installation.

Horsepower gains are modest—usually in the 4–7 hp range when paired with a cat-back system—but the improvement in throttle response and exhaust tone is immediately apparent. The sound is louder than stock but not obtrusive, with a deep rumble that becomes more aggressive under wide-open throttle. Agency Power also offers a resonated version for those who want to keep noise levels in check for track-day sound limits. The price point makes this an attractive entry-level option, though some users note that the included hardware could be higher quality. For a budget-conscious build, the Agency Power midpipe delivers solid results.

HKS Midpipe

HKS has been engineering performance exhausts for decades, and their midpipe for the Subaru BRZ/Toyota 86 continues that tradition. The HKS midpipe features a 70mm (approx. 2.75-inch) diameter made from SUS304 stainless steel with a distinctive straight-through resonator design that reduces backpressure while maintaining a rich exhaust note. HKS uses a special flange design that ensures a leak-free connection to both the front pipe and the cat-back, and the pipe is mandrel-bent for consistent internal diameter throughout.

The HKS midpipe is particularly well-regarded for its sound quality: it delivers a crisp, sporty tone that is unmistakably boxer, with minimal drone thanks to the precisely tuned resonator. It pairs beautifully with the HKS Legamax cat-back exhaust, creating a symphony that enthusiasts call "the HKS sound." Driving feel benefits from improved mid-range torque, and the system weighs about 2.5 kg less than the stock pipes. The main downside is availability—HKS parts can be hard to find in some markets—and the price is at the premium end. But for purists who respect Japanese engineering heritage, the HKS midpipe is a top-tier choice.

Factors to Consider When Choosing a Midpipe

Selecting the right midpipe for your BRZ or 86 involves evaluating several technical and practical aspects. Below are the most important considerations to guide your decision.

Material and Construction

Most aftermarket midpipes use T304 stainless steel, which offers excellent corrosion resistance and high-temperature strength. T304 is the industry standard for performance exhausts because it can withstand heat cycling without warping and maintains a polished appearance for years. Some budget options use T409 stainless steel, which contains less chromium and is more prone to rust, but it costs less. For weight savings, titanium midpipes are available from select manufacturers, but they are much more expensive and require specialized welding. Always choose a midpipe with mandrel bends (not crush bends) to preserve exhaust flow; mandrel bending maintains a consistent inside diameter through the curve.

Diameter and Flow

The factory midpipe is approximately 2.25 inches in diameter. Moving to 2.5 inches improves flow for naturally aspirated builds and mild bolt-on combinations without losing exhaust velocity. For forced induction (supercharger or turbo) or high-performance naturally aspirated setups (e.g., headers + cams + tune), a 3-inch midpipe provides the necessary volume to prevent restriction. Going overly large on a stock engine can reduce low-end torque due to loss of scavenging effect. If you plan to add forced induction later, a 3-inch midpipe is an excellent long-term investment.

Sound Profile and Drone

Midpipes with internal resonators (chambered or perforated tube designs) will produce a deeper, more refined tone with less interior resonance. Resonator-delete midpipes (straight pipes) are louder and more aggressive but often create drone at highway speeds, which can be fatiguing on long drives. Listen to sound clips from trusted sources (this sound comparison video is a good start) and consider your tolerance for loudness. Some manufacturers offer optional "quiet" resonators for those who need to pass sound regulations at track days.

In many regions, removing the catalytic converter or resonator can violate emissions laws and vehicle inspection requirements. Some aftermarket midpipes include a high-flow catalytic converter or a resonator that maintains O2 sensor readings. For example, the Perrin Performance midpipe includes a built-in resonator but no cat, which may still be illegal in California and other CARB states. Check local regulations before purchasing. If you need to pass a visual inspection, choose a midpipe that retains a catalytic converter (like the Crawford Performance midpipe) or a "ghost" cat design that masks the fact the catalyst is missing.

Compatibility and Installation

Most midpipes bolt directly to the stock front pipe and cat-back system, but aftermarket headers or front pipes may have different flange angles or diameters. Confirm compatibility: some midpipes require a specific cat-back system (e.g., Invidia Q300 midpipe pairs best with Invidia Q300 cat-back). Also check the number of flanges (two or three-piece designs) and whether gaskets and hardware are included. The installation is manageable for a DIY mechanic with ramps or jack stands—no permanent modifications needed. Expect 30–60 minutes if the bolts are not rusted. Use anti-seize on the bolts when installing to ease future removal.

Budget and Value

Midpipe prices range from about $200 (entry-level stainless) to over $600 (premium titanium or brand names). A $300–$450 midpipe from a reputable brand like Invidia or GReddy often represents the best balance of quality and cost. Avoid the cheapest no-name options, as they may have poor welds, thin flanges, and mismatched fitment that cause leaks or rattles. Spending a little more on a proven product saves frustration and delivers better performance and sound.

Installation Tips and Considerations

Before starting the install, park on a level surface and allow the exhaust to cool completely. Apply penetrating oil (e.g., WD-40 or PB Blaster) to the flange bolts and hanger studs 30 minutes beforehand, especially if the car is several years old. You will need a 12mm or 14mm socket, a ratchet extension, a torque wrench, and possibly a hammer to loosen stubborn hangers. The stock hangers can be stiff; using a rubber hanger removal tool or lubricant (like dish soap) helps slide the new midpipe on.

When installing, tighten all bolts to the manufacturer's torque specifications (typically 25–35 ft-lbs). Use a crisscross pattern on flanges to ensure even pressure. Start the car and check for exhaust leaks by listening for hissing sounds or using a soapy water spray on joints. A small leak can cause a worrisome sound but is usually fixed by re-torquing the bolts. If you are pairing the midpipe with a new cat-back, do not tighten everything fully until the entire system is aligned, then tighten from the front back.

For additional tips, the FT86 Club forums have detailed write-ups with photos from owners who have installed various midpipes. Reading a few threads will clarify common pitfalls and specific advice for your chosen product.

Tuning and Performance Gains

While a midpipe alone provides a modest power increase (usually 3–8 horsepower), its real value is as part of a complete exhaust system. When combined with aftermarket headers and a cat-back, a midpipe can help unlock 15–20 wheel horsepower with a proper tune (e.g., using an ECUflash or OpenFlash tablet). The improvement in exhaust flow allows the engine to breathe more freely, reducing pumping losses and lowering exhaust gas temperatures. This also contributes to a small increase in fuel economy during normal driving, though the temptation to enjoy the new sound often outweighs that benefit.

If you plan to tune your car, choose a midpipe with a consistent diameter that matches your headers and cat-back for a smooth transition. Avoid neck-downs or step-ups that create turbulence. For naturally aspirated builds, a 2.5-inch midpipe is optimal; for turbo builds, 3 inches is strongly recommended. Many professional tuners suggest pairing the midpipe with a cold-air intake and a tune for maximum gains from the exhaust upgrade. A dyno-tuned car with a full exhaust system and midpipe can see throttle response improvements that transform the driving experience, especially on track days.

Conclusion: Choosing Your Midpipe

Upgrading the midpipe on your Subaru BRZ or Toyota 86 is an effective, rewarding mod that improves sound, performance, and driving engagement. The Invidia Q300 offers a balanced, quality build for daily drivers; GReddy delivers proven engineering and reliability; ARK Performance prioritizes sound refinement and craftsmanship; Agency Power provides excellent value for budget builders; and HKS brings iconic Japanese tuning heritage and exhaust note shaping. Each option has its strengths, and your choice should align with your power goals, sound preferences, and local legal constraints.

No matter which midpipe you select, installation is straightforward, the gains are immediate, and the smile on your face will grow with every rev. For more community feedback and reviews, check out discussions on r/ft86 on Reddit where owners share real-world experiences. Happy building, and enjoy the improved exhaust note of your twin.