UNEQUAL LENGTH HEADER - 04-21 STI, 02-14 WRX, 04-13 FORESTER XT, 05-09 LEGACY GT, 05-09 OUTBACK XT
SKU: 80469280615

UNEQUAL LENGTH HEADER - 04-21 STI, 02-14 WRX, 04-13 FORESTER XT, 05-09 LEGACY GT, 05-09 OUTBACK XT

Sale price$449.55 Regular price$499.50
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Description

UNEQUAL LENGTH HEADER - 04-21 STI, 02-14 WRX, 04-13 FORESTER XT, 05-09 LEGACY GT, 05-09 OUTBACK XTClassic Subaru Sound with Unparalleled Performance Over the years, GrimmSpeed Engineers have proven that we are capable of manufacturing the highest quality, best performing exhaust components for the Subaru aftermarket. While we might not always be the first to release a certain product, our major advantage is that we can take our time in testing and development, putting the product through countless hours and thousands of miles of testing. This

Classic Subaru Sound with Unparalleled Performance

Over the years, GrimmSpeed Engineers have proven that we are capable of manufacturing the highest quality, best performing exhaust components for the Subaru aftermarket. While we might not always be the first to release a certain product, our major advantage is that we can take our time in testing and development, putting the product through countless hours and thousands of miles of testing. This ultimately ensures that once a component is in your hands, it will be the most-refined version of that product available. The all new GrimmSpeed Unequal Length EJ Header is a perfect example of this.

Our Unequal Length Header for the EJ-Series engines is very much the same. There are countless options out on the market for high-performing equal length header, but if you want to keep that classic Subaru rumble, there aren’t many great options.

The OEM EJ header really hasn’t changed much in the past 20+ years and it shows. The tight geometry and long cross-pipe between the two collectors are not optimized for flow or power. While the smaller diameter and volume may be good for low-end spool, the factory header gets choked out higher in the rev range. Simultaneously, it's known that swapping to a more-equal length manifold with larger diameter runners offers additional performance potential. We set out to create a header that would be the best of both worlds, offering great performance and the unique sound that makes your car unmistakably a Subaru!

While other aftermarket unequal length headers use different runner lengths for each cylinder, our proprietary design utilizes an innovative setup where each bank of runners are equal length, but one set is 1.5 time the length of the other, providing the rumble sound that we all love while maintaining the performance of an equal length setup. We utilize single piece, mandrel bent runners to minimize disturbances to the exhaust gas along with an extremely durable cast 304 stainless steel collector to achieve keep each back of runners truly equal length which would be difficult to accomplish with a 4-into-1 welded collector. The low angle merge this collector makes for faster spool and unbeatable off-boost throttle response. To match this flow, the collector features machined internal diameters to perfectly match the 1 ¾” primary runners and 2” secondary pipe, eliminating unwanted “steps” in the exhaust flow.

As with all of our exhaust components, our Unequal Length Header features ½ inch flanges for both the heads as well as the up-pipe side. These combined with the 14 gauge runner pipes make for extreme durability and heat retention.

We started the R&D process by scanning the underside of of several EJ engine setups using a FARO arm. This allowed us to design and simulate our header in a digital 3D space to find the optimal balance of runner lengths and angles for the best performance possible on an unequal length setup. Next, we were able to 3D-print a variety of different configurations that would allow us to narrow in on the most optimal final design. During this process, we were able to form the header around a variety of different STI oil pan setups, from the factory pan to aftermarket options like those offered by IAG and Killer B Motorsports. After we were satisfied, we made pre-production prototype units that were put through months of punishing performance and longevity testing.

To validate our simulated performance, we did extensive real-world dyno testing comparing our header design to the factory header as well as some of the most popular headers on the market, both unequal length and equal length. For our testing, we used a 2010 STI with the stock turbo and basic bolt-ons as well as our 2020 STI shop car with full GrimmSpeed Stage 3 bolt-ons, E85, and a GrimmSpeed BB500 turbocharger. Throughout all of our testing, we kept the same tune loaded as well, so the only variable was the header that was installed.

The GrimmSpeed Header out spooled the competition’s equal length header by 50rpm while making similar boost levels. Our Header produces more torque than the equal length manifold right out of the gate, producing about 15ftlbs more throughout spool up. At peak, the GrimmSpeed Header was able to produce and extra 2 ft/lbs of torque and an additional 21 hp compared to the equal length setup.

Quick Specs

  • Innovative 1.5 to 1 Unequal Length Runners - Each bank of runners is equal length, allowing for equal length performance with an unequal length sound
  • 4-into-1 Low-Angle Merge Cast Collector - Ensure minimal restriction and maximum performance
  • Smooth, Restriction-Free Flow Throughout – Single piece mandrel bent tubing welded to a single piece merge collector removes unwanted “steps”
  • Substantial Power/Torque Gains - +25hp and +25ft/lbs of torque over stock
  • Quickest Spooling Aftermarket Header - Faster spool and more power compared to the competition
  • No Tune Required – Safe to run, just bolt on
  • Gaskets and Hardware Included – Everything you need to get installed and on the road
  • Designed To Fit With Aftermarket Oil Pans - Fits with the STI oil pan or popular aftermarket options
  • Full 304 Stainless Steel Construction - 1/2" flanges and 14ga runners for extreme durability
  • Manufactured and Welded In The USA – For consistency and top quality control

Fitments

  • 04-21 Subaru STI
  • 08-14 Subaru WRX
  • 09-13 Subaru Forester XT*
  • 05-09 Subaru Legacy GT*
  • 05-09 Subaru Outback XT*
  • 02-05 Subaru WRX 5MT (Requires STI Oil Pan and Pickup)
  • 06-07 Subaru WRX (Requires STI Oil Cooler and Feed Pipe)
  • 04-08 Subaru Forester XT* (Requires STI Oil Pan, Pickup, and Oil Cooler)
  • 04-06 Subaru Baja XT* (Requires STI Oil Pan, Pickup, and Oil Cooler)
Shipping Notes
  • Free Standard Shipping on $100+ Orders to the USA.
  • Except Preorder products are shipped in 48 hours.
  • Delivery to the USA:
  1. Standard Shipping : 3-10 business days
  • If time is of the essence, please consider selecting expedited delivery for faster service.
Exchange/Return Notes
  • We offer a 30-day return/exchange service after receiving.
  • Final sale items are not eligible for returns or exchanges.
  • To process your return/exchange, please contact us at [email protected]
  • Please click here for more details>>> Return & Exchange Policy
SKU: 80469280615

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Lo
Draper, US
★★★★★ 5
Great shelves
Size: 24 Inch, Color: White
Easy to assemble and comes with everything you need for drywall or wood. Nice color and texture and comes with stickers to hide the holes underneath. I bought two sets of three. These are very long, so I recommend just using two at a time.
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Reviewed in the United States on February 8, 2026
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JRay
Birmingham, US
★★★★★ 5
Eye pleasing shelves with the ability to hold weight
Color: Light Brown, Size: 4
Great set of 4 wood floating shelves. I used these to hold precon decks and other commander decks for magic the gathering cards. Though they are on the smaller size, they still fit up to 4 commander boxes side by side and and withhold double that if I stack the boxes. I am very impressed by the quality and how much weight each shelf can hold. The brackets to hang them make the shelves even more sturdy. The shelves are very pleasing on the eyes and the wood color is very natural. The shelves were simple to hang by one person. They look very stunning and of great value. They hold all kinds of items and function perfect as a shelf and look wonderful as a form/type of wall decoration even without items on the shelves. Overall I’m very happy with this purchase and I will be buying more of these shelves soon.
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Reviewed in the United States on May 27, 2025
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Michelle Marley
Boise, US
★★★★★ 5
Great shelves
Color: Light Brown, Size: 4, Color: Light Brown, Size: 4
These are cute and easy to install. They were the perfect size for the location. I did use other drywall mounts to make sure they were more likely to stay in but after I installed they feel sturdy and reliable.
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Reviewed in the United States on October 14, 2025
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Mercy Lovell
Chelsea, US
★★★★★ 5
Great Product
Color: Brown, Size: 4
Love them! They’re fairly priced and can hold a lot of weight! Make the space look great!
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Reviewed in the United States on March 25, 2026
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Joseph Sohn
Waukegan, US
★★★★★ 3
Different mounting mechanism than photos
Color: Light Brown, Size: 4, Color: Light Brown, Size: 4
I'm going to start off this review by stating that the mounting mechanism used on the Shelf is different than the one shown in the photo. In the photo, it shows a single bar which would have made the Shelf easier to level however, the product I received has two separate bars which means I have to be extra careful holding a level against the paper. Stencil. The reason I chose this product over different listings was because for a dollar or two more its photo showed a single bar. Now for the pros and cons: Pros: Accurate measurement. Shelf appears to be actual wood! The photos made it looks like a veneer, which it is not. Easy to install. Includes good instructions. Seems like it can hold items fairly well. Cons: The mounting hardware for drywall pretty flimsy, and I stripped out some of the drywall anchors during install. They still worked, but it was annoying to finish inserting them. The shelf doesn't sit fully flush to the wall from factory as the screws included make it protrude slightly. I can fix this with my dremel, However, This could have been solved from the factory by making the cavity slightly deeper. As mentioned above in my main detractor, it is a two bar mounting system rather than a one bar, which was shown in the photo.
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Reviewed in the United States on October 21, 2024

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