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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Ships within 48 hours · Estimated delivery Sep 18 - Sep 23

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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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4.1 ★★★★★
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Verified Purchase
Jay T.
Houston, US
★★★★★ 5
Works well in home office.
Color: Black, Size: 8 Outlet, Style: Outlets Only
Nice layout of outlets. Sturdy construction. Flat electrical plug. Works well in home office.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on February 24, 2025
R
Verified Purchase
Robert MacIntel
Lexington, US
★★★★★ 5
APC is a trusted brand - this guy is beautifully thought out!
Color: Black, Size: 8 Outlet, Style: Outlets Only
It's hard to get excited about a power strip- but when they designed this one, the engineers at APC hit it out of the park! I love how the 'wall warts' (those odd klunky AC/DC power adapters that so many devices come with nowadays) have their own spot on this unit, and do not block out the remaining plugs that regular AC power cords (3 prong grounded) require. This is VERY important! Most of the competition has you forfeiting one or more plug locations when a wall wart blocks you out! There are on/off status lights (green means OK) and and on/off SWITCH. For the modest and reasonable cost, you get great surge protection. I have used APC products for many years, particularly fond of their backup UPS power supplies. I plan to buy more of this model for my apartment. The quality is there, a nice heavy line cord to connect to the AC power, and better-than-average build quality. Slick!
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Reviewed in the United States on March 15, 2019
C
Verified Purchase
cryomerlin
Chelsea, US
★★★★★ 4
It works but not so sure about the EMI/RFI noise filtering claim
Color: Black, Size: 8 Outlet, Style: Outlets Only
I only buy surge protectors that have EMI/RFI noise filtering. I have a sensitive short wave radio with a sleep timer that I use when going to sleep. It has a rechargeable battery so you can either use it plugged in or on battery power. I've always had static on the radio when it was plugged into this surge protector. Cords generally do cause interference in radios so I thought nothing of it. But it started to get really bad. So I took one of my old tripplite surge protectors with emi/rfi noise filtering and plugged the radio into that. No static or interference on the radio at all. I went to APC's website to see if this model has EMI/RFI and it looks like it does....but it sure doesn't work well on mine. I don't want to disparage APC. I have several of their surge protectors. Just bought the big P12U2 model they have and love that one. I think it just has better circuitry than this budget model. I'm using the P12U2 on my TCL 55" TV that was flickering and was glitchy turning on and off with a different surge protector from another company. Anyways, the ACP P12U2 works great and appears to have excellent noise filtering. Just wish the P12U2 had a flat plug because I bought it to use for my computer, but couldn't because I couldn't push my desk up against the wall with that straight out plug. Anyways, I've strayed. This is a good basic surge protector I suppose. Would not recommend it for sensitive electronics prone to interference. Then again, maybe I just had a bad one, who knows. APC is a great brand. All my surge protectors are either APC or TrippLite. Can't go wrong either way.
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Reviewed in the United States on January 28, 2022
A
Verified Purchase
Amazon Customer
Alexandria, US
★★★★★ 5
Great surge protector
4 years later and still working as intended.
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Reviewed in the United States on March 22, 2026
S
Verified Purchase
Savvy Shopper
Omaha, US
★★★★★ 5
It Works
This works fine. Good size. Good enough cord length. Does what a power strip should do.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on March 21, 2025

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