After researching hundreds of owner reviews and comparing manufacturer spec sheets, we selected the seven best Subaru aftermarket parts that consistently deliver on performance, durability, and value. From cold air intakes to exhaust systems and suspension upgrades, each product was evaluated against industry standards and real-world feedback. We highlight genuine strengths and weaknesses, so you can choose the right part for your build without overspending.
| Photo | Product | Score | Buy |
|---|---|---|---|
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COBB Tuning SF Intake + Airbox Best Cold Air Intake Fits Subaru WRX/STI 2015+; washable dry filter; CARB exempt (EO D-660-13) |
9.2 | 🛒 Check Price |
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Bilstein B6 4600 Series Shock Absorbers Best Suspension Upgrade Direct replacement for Outback/Legacy 2010-2019; monotube gas pressure design |
9.0 | 🛒 Check Price |
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Perrin Performance Lightweight Crank Pulley Best Engine Performance Mod Fits Subaru FA20DIT and EJ25; 6061 aluminum; 1.5 lbs vs 5 lbs stock |
8.7 | 🛒 Check Price |
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Invidia N1 Cat-Back Exhaust System Best Exhaust System 304 stainless steel; 3-inch piping; dual 4-inch burnt titanium tips |
8.4 | 🛒 Check Price |
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Whiteline Adjustable Rear Sway Bar (24mm) Best Handling Upgrade Fits Subaru Impreza/WRX 2008-2014; 3-hole adjustable; includes polyurethane bushings |
8.1 | 🛒 Check Price |
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Kartboy Short Throw Shifter + Bushings Best Shifter Upgrade Fits Subaru WRX/STI 2002-2021; reduces throw by 40%; includes front and rear bushings |
7.8 | 🛒 Check Price |
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Subaru OEM All-Weather Floor Liners Best Interior Protection Custom-molded for Outback/Forester/Crosstrek 2020+; raised edges; TPE material |
7.3 | 🛒 Check Price |
1. COBB Tuning SF Intake + Airbox: Best Cold Air Intake
In our evaluation, the COBB Tuning SF Intake stands out for its engineered balance of performance and reliability. The sealed airbox design minimizes heat soak, and the washable dry filter eliminates the need for oiling. Owner feedback confirms consistent gains of 10-15 hp on the stock tune, and the included pre-filter extends service intervals in dusty environments. However, the price is higher than open-element intakes, and some users report that the filter can be tricky to seat properly on the first install.
This intake is ideal for WRX and STI owners seeking a proven, CARB-legal upgrade that doesn’t require a custom tune. Skip it if you’re on a tight budget or prefer the louder induction noise of an open intake, as the sealed box dampens sound significantly.
- Gains up to 15 hp and 12 lb-ft torque with stock tune
- Sealed airbox reduces intake noise and heat soak
- Includes pre-filter sock for dusty conditions
Pros: Excellent power gains with no tune required; High-quality construction with silicone hoses
Cons: Premium price compared to simpler intakes
2. Bilstein B6 4600 Series Shock Absorbers: Best Suspension Upgrade
We compared Bilstein B6 shocks against OEM and other aftermarket options, and they consistently delivered superior damping control. The monotube construction handles heat buildup better during spirited driving, and owner reports indicate they last well over 100,000 miles under normal use. However, installation requires spring compression and can be challenging for DIYers without proper tools; professional installation is recommended.
These shocks are best for Outback and Legacy owners who want sharper handling without lowering the vehicle. They are not suitable for those seeking a plush, cloud-like ride, as the firmer valving transmits more road imperfections.
- Improves handling and reduces body roll significantly
- Monotube design dissipates heat better than twin-tube
- Lifetime limited warranty
Pros: Noticeably better ride control and stability; Built to last with corrosion-resistant coating
Cons: Firmer ride may be too stiff for some daily drivers
3. Perrin Performance Lightweight Crank Pulley: Best Engine Performance Mod
Our research shows that the Perrin lightweight crank pulley reduces rotating mass by over 3 pounds, which translates to faster revs and a more responsive engine. The 6061 aluminum construction is durable, and the anodized coating prevents corrosion. However, some owners report a slight increase in accessory belt noise and minor vibrations at idle, which can be mitigated by proper belt tension adjustment.
This mod is ideal for enthusiasts looking for a relatively inexpensive way to improve throttle response. Skip it if you are sensitive to NVH (noise, vibration, harshness) or if your car is still under warranty, as some dealers may flag the pulley during service.
- Reduces rotational mass for quicker throttle response
- Anodized finish resists corrosion
- Includes ARP hardware for secure installation
Pros: Noticeable improvement in engine revving; Easy installation with basic hand tools
Cons: May cause minor vibrations at idle
4. Invidia N1 Cat-Back Exhaust System: Best Exhaust System
After comparing multiple exhaust systems, the Invidia N1 stands out for its balance of sound and build quality. The 304 stainless steel and TIG welding ensure long-term durability, and owner feedback highlights the deep tone that doesn’t drone on the highway. However, the 4-inch tips are quite large and may require trimming of the bumper on some models, and the system is louder than stock, which may attract unwanted attention.
This exhaust is perfect for WRX and BRZ owners who want a sporty sound without excessive noise. It is not recommended for those who prefer a near-silent ride or who live in areas with strict noise ordinances.
- Deep, aggressive exhaust note without drone
- TIG-welded construction for strength and longevity
- Bolt-on installation with included gaskets and hardware
Pros: Excellent sound quality with no highway drone; Corrosion-resistant stainless steel
Cons: Large tips may not fit all bumper cutouts
5. Whiteline Adjustable Rear Sway Bar (24mm): Best Handling Upgrade
In our evaluation, the Whiteline adjustable rear sway bar effectively reduces understeer and improves turn-in response. The three adjustment holes allow drivers to dial in oversteer or neutral handling. However, the polyurethane bushings require periodic greasing to prevent squeaks, and installation can be tricky on rust-prone vehicles. Some owners report that the bar is slightly thicker than advertised, requiring careful fitment.
This bar is best for autocross or track-day enthusiasts who want to sharpen handling. It is not ideal for daily drivers who prioritize comfort, as the stiffer rear end can make the car feel twitchy on bumpy roads.
- Reduces understeer and improves cornering grip
- Adjustable to fine-tune handling balance
- Greaseable bushings for long life
Pros: Noticeable reduction in body roll; Easy adjustment with included hardware
Cons: Poly bushings can squeak if not lubricated regularly
6. Kartboy Short Throw Shifter + Bushings: Best Shifter Upgrade
We researched owner feedback on the Kartboy short throw shifter and found it consistently reduces throw length and tightens the shift gate. The included bushing kit eliminates the rubbery feel of the stock shifter. However, the increased mechanical leverage results in higher shift effort, which can be fatiguing during daily commuting. Some users also report that the lever can vibrate at high RPM if not installed with threadlocker.
This upgrade is great for performance drivers who want a more connected feel. Skip it if you have shoulder or wrist issues, or if you primarily drive in stop-and-go traffic.
- Shorter, more precise shifts with reduced slop
- Anodized aluminum lever resists wear
- Bushing kit improves shifter feel dramatically
Pros: Noticeably tighter shift action; Easy to install with basic tools
Cons: Increased shift effort may be tiring in traffic
7. Subaru OEM All-Weather Floor Liners: Best Interior Protection
Based on owner feedback, the Subaru OEM all-weather liners offer the best fit of any aftermarket mat, with raised edges that trap snow, mud, and spills. The TPE material is odor-free and withstands extreme temperatures. However, the surface can be slippery when wet, which is a safety concern for driver foot slippage. Additionally, the rear seat mat may not cover the transmission tunnel hump completely on some models.
These liners are ideal for outdoor enthusiasts who frequently track mud or snow into the car. They are not recommended for those who prioritize a plush carpet feel or who need maximum anti-slip grip.
- Precise fit with coverage over dead pedal
- Easy to clean with soap and water
- Non-slip surface keeps cargo in place
Pros: Perfect fitment with no gaps; Durable TPE material resists cracking
Cons: Can be slippery when wet
Frequently Asked Questions
Which aftermarket part gives the best horsepower gain for a Subaru WRX?
Based on our research, a cold air intake like the COBB Tuning SF Intake can add 10-15 hp on a stock tune. For larger gains, a downpipe and tune are needed, but that combination may affect emissions compliance.
Are aftermarket parts covered by Subaru warranty?
Generally, aftermarket parts are not covered by the factory warranty. However, the Magnuson-Moss Warranty Act prevents dealers from voiding the warranty unless they can prove the aftermarket part caused a failure. Choose CARB-legal parts to minimize risk.
Do I need a tune after installing a cat-back exhaust?
No, cat-back exhausts do not require a tune because they do not alter the exhaust system before the oxygen sensors. They primarily change sound and add minimal power on turbocharged engines.
How often should I replace the air filter on a cold air intake?
Most washable filters, like the one on the COBB intake, should be cleaned every 30,000 miles or when visibly dirty. In dusty conditions, more frequent cleaning is recommended. Follow the manufacturer’s instructions to avoid over-oiling.
Will a lightweight crank pulley damage my engine?
Reputable lightweight pulleys like the Perrin unit are designed to be safe for daily driving. However, some aftermarket pulleys without harmonic dampers can cause bearing wear over time. The Perrin pulley is balanced and has not shown widespread issues in owner reports.
Our Verdict
After comparing specifications, owner feedback, and industry standards, the COBB Tuning SF Intake earns our top pick for its proven power gains, excellent build quality, and CARB compliance. For those prioritizing handling, the Bilstein B6 shocks are a close runner-up, offering transformative ride control with long-lasting durability.
Last reviewed and spec-checked: April 17, 2025. We re-check our picks and listings periodically.
