GrimmSpeed 15-21 WRX Equal Length Exhaust Header | 113008

• 2015-2021 Subaru WRX

The Highest Quality, Built to Last!

Over the years, GrimmSpeed has proven that our exhaust products are some of the highest-quality and best-performing in the industry because of the detail oriented approached that we put into their development. When it comes to improving on an OEM design, this attention to detail and overall exhaust knowledge allows us to identify aspects of the factory parts that can be greatly improved upon. One of the first things to note about the OE exhaust manifold are the several points where flow is decreased due to a neckdown in piping diameter. These disruptions in exhaust flow result in decreased turbine efficiency which ultimately limits boost and power production. Furthermore, the OE merge collectors are made specifically with ease of manufacturing in mind and the result is a compromise on performance. The collectors contain very odd shapes that are bad for smooth exhaust flow and have several diameter restrictions that make them one of the biggest weaknesses of the stock manifold. Finally, the angle of the exhaust flow merge is also not ideal, causing the exhaust pulses to “fight” each other, which can add to flow differences for the twin scroll turbine, sacrificing spool and performance.

After isolating the inadequacies of the OEM exhaust manifold, we were able to start identifying key areas of improvement: correctly sized and consistent exhaust runners that are more equal length, a consistent and non-bottlenecking merge collector inlet and outlet and a higher angle merge collector to direct flow into the turbine and prevent opposing flow disruptions. Beyond that, we decided on using thicker tubing and flanges for increased durability and longevity to more-effectively support the overhanging turbocharger.

All four of our exhaust runners are designed in conjunction with the merge collector to equal out the lengths as well as the overall bend angles. This is especially important in the FA WRX twin scroll turbine configuration because it makes the strength of each pulse, or “push” on the turbine wheel, at equal timing and consistency.

Since the exhaust runners are CNC bent and trimmed as a single piece there are no additional welds to introduce points of failure or junctions that would interrupt flow, resulting an in impressive difference of less than 1% in total length. In addition, maximum variance is only 5 degrees from the most bent to the least bent runner, this mean we were able to produce what is a truly equal length, and equal bend manifold. The collector being cast, allows for the runner spacing and angles necessary to obtain the equal bends and lengths of all the tubes. This part is a major player in the GrimmSpeed manifold’s ability to fit between the stock skid plate and the oil pan while still providing the ideal performance from the rest of the design. The cast collector also allows for more smooth and consistent flow in the interior compared to a welded variant. This greatly simplifies the overall design, removing five more welded junctions, which could be a point for flow interruption or the structural failure that we see with other headers.

The head flanges of our header are CNC cut and faced from a 1/2in thick piece of 304 stainless steel. This design is much thicker than OEM to increase reliability and longevity, as well as to provide additional material to be removed after welding to ensure flatness from flange to flange. This additional measure allows for greater gasket sealing which results in increased performance. The final touch is that the exhaust runners are welded inside the flange as well as outside, this is an extra step in manufacturing, but it provides a rounded lip to improve flow from the flange through the runner.

All of these things come together to make The GrimmSpeed 15-21 WRX Header not only the prettiest on the market, but also among the best performing and durable pieces you can purchase.

Quick Notes:

• Full 304 Stainless Steel Construction – Flanges, tubing, collector and badge

• True Equal Length Runners – CNC bent and trimmed, less than 1% variance from the longest to the shortest

• Innovative Cast Merge Collector – Low restriction inlet and outlet, smooth flow and consistent performance

• Smooth, Restriction-Free Flow Throughout – Single piece mandrel bent tubing welded to a single piece merge collector removes unwanted “steps”

• Thick 1/2in CNC Cut Flanges and 14ga Tubing – Added durability and longevity

• No Tune Required – Safe to run, just bolt on

• No Ground Clearance Loss – Clears factory skid plate without using spacers

• J-Pipe/Turbo Bracket Included – Retain the support that other aftermarket header lose

• Gaskets and Hardware Included – Everything you need to get installed and on the road

• Manufactured and Welded In The USA – For consistency and top quality control

Fitments:

• 15-21 Subaru WRX

Video Install Guide:

Video - GrimmSpeed Equal Length Header Install - 15-21 Subaru WRX

At JDMuscle, we understand that fast and reliable shipping is crucial. With multiple distribution centers across the nation, most in-stock items are shipped within 1-2 business days. On average, you can expect delivery within 1-5 business days for in-stock items. Please note, however, that some products may ship directly from vendors, which could result in additional delays. Products sourced from overseas may also take longer to arrive.

Free Shipping over $199 Policy

• Free shipping is available only for the 48 contiguous states in the U.S.
• Ground shipping applies to regular-sized items only.
• Oversized items such as lips, hoods, and trunks requiring freight shipping are not included in the free shipping program.
• Some manufacturers may impose a shipping surcharge, which will be excluded from the free shipping program.
• The most accurate shipping costs will be displayed at checkout. If you believe the shipping cost is incorrect, please contact us at sales@jdmuscleusa.com for further review.

Carriers

We ship via FedEx, UPS, USPS, and DHL. While we strive to use the most efficient option, we cannot guarantee which carrier will deliver your order. Your items may arrive in multiple packages through different carriers.

Processing Time and Shipping Cut-off

Orders typically take 24 hours to process, with shipping cut-off at 3:00 PM EST. Transit times vary based on location and carrier. Some items, especially those requiring freight shipping, may have extended processing and delivery times. For freight shipping inquiries, contact us at sales@jdmuscleusa.com.

International and Special Shipping Considerations

• International orders are subject to higher shipping fees. If you would like to review your shipping cost, email us at sales@jdmuscleusa.com with your full address and items you plan to purchase.
• In some cases, shipping costs may be incorrectly calculated for international or oversized items. We reserve the right to adjust the shipping fee and will work with you to negotiate a fair cost if needed.
• Customers can challenge and request a review of international shipping fees, and we’ll do our best to find a lower rate where possible.
• Customs Fees & Import Taxes: The shipping charge you pay does not include customs fees or import taxes. These charges vary by country and are the customer’s responsibility. Please check with your local customs office for more details before placing an order.
• Shipping Cost Adjustments: Shipping rates fluctuate, and while we strive to provide the most competitive rates, there may be instances where the shipping cost you paid is significantly lower than the actual cost. In such cases, we reserve the right to request the difference to ensure we cover our basic expenses. We appreciate your understanding and will always aim to keep shipping costs as affordable as possible.

Address Modifications and Fees

• Any modifications to a shipping address after an order is placed may be subject to additional fees.
• For single, small packages, the flat fee is $20. For larger or multiple packages, the fee may be up to $60 or more.

Freight Shipping Guidelines

• Freight shipments require you to be present at the time of delivery.
• The delivery driver may provide a delivery receipt (Bill of Lading). It is crucial to inspect the shipment before signing.
• Carefully check the packaging for any visible damage (dents, punctures, rips) and notate it on the Bill of Lading.
• Open the package and inspect the product itself. If damage is found, document it in detail on the Bill of Lading, take photos, and contact the shipping company to initiate a damage claim.
• Do not refuse the shipment. Contact us at sales@jdmuscleusa.com for guidance.
• If the delivery driver is unable to wait for inspection, note this on the Bill of Lading.

Failure to document damages before signing the Bill of Lading will void any claims for refunds or replacements.

Pre-Installation Inspection Policy

We strongly recommend inspecting all parts or items upon arrival before installation. If you identify any damage, imperfections or missing components, report them immediately to sales@jdmuscleusa.com. Do not install the item. Please note that reports of damage, defects, imperfections or missing components after installation will NOT be honored.

Package Protection

We do our best to ensure your items arrive to you safely but sometimes things happen. If you utilized our Checkout+ feature, rest assured that your package is protected! With package protection, in the event that your package is lost, stolen, or damaged while in transit, we will replace it free of charge. To start a shipping claim, please click here.

Need Assistance?

If you have any concerns about shipping costs or transit times, or if you notice discrepancies during checkout, feel free to reach out to us at sales@jdmuscleusa.com. We’re happy to assist you and ensure a smooth delivery experience.

Our policy lasts 30 days. If 30 days have passed since your purchase, unfortunately, we can’t offer you a refund or exchange. To initiate a return, please email us at sales@jdmuscleusa.com.

Eligibility for Returns

✅ Items must be unused and in the same condition as when received.
✅ Items must be in their original packaging.

Non-Returnable Items

❌ Gift cards
❌ Special-order or custom products

How to Initiate a Return

📧 Include the following details in your return request email:

Order Number

Item(s) to be returned

Reason for return

Important Notes:

Do NOT send your purchase back to the manufacturer.

Do NOT return any items without first setting up a return request with us.

Partial Refunds

Partial refunds may be granted under the following conditions:

⚠️ Items not in original condition, damaged, or missing parts not due to our error.
⚠️ Items returned more than 30 days after delivery.

Restocking Fees

Some manufacturers may charge a restocking fee, which includes but not limited to:

ManufacturerRestocking Fee

ESR30%

JDMuscle15%

PLM & Option Lab 20%

Cancellations

Before placing an order, please confirm availability.

Cancellations within 7 days may be subject to fees to cover third-party transaction costs.

Once the order has been processed (packaged or tracking generated), cancellations are not allowed. Eligible items may be returned instead.

Special-order items cannot be canceled.

Refund Process

🔄 Once your return is received and inspected, we will notify you of the refund status.
💳 Approved refunds will be credited back to your original payment method within 3-10 business days (depending on the payment provider).

Late or Missing Refunds

🔍 Check your bank statement — sometimes the refund may not appear as a new entry but as the disappearance of the pending charge. 📞 Contact your credit card or financing company — they may require additional time for processing.

If you’ve done all of the above and still haven’t received your refund, email us at sales@jdmuscleusa.com for assistance.

Sale Items

Only full-priced items are eligible for returns and refunds.

Exchanges

We replace items only if they are defective or damaged. To request an exchange for the same item, email us at sales@jdmuscleusa.com.

Gifts

🎁 If the item was marked as a gift when purchased and shipped directly to you, you will receive a gift credit for the return value.
📩 If the gift giver had the item shipped to themselves, we will refund the gift giver.

Return Shipping

📦 Customers are responsible for return shipping costs unless the item is damaged, defective, or incorrect (in which case we will cover shipping both ways).

Initial shipping costs are non-refundable.

Return shipping costs will be deducted from the refund amount.

For items over $75, consider using a trackable shipping service or purchasing shipping insurance. We are not responsible for lost or damaged items during return shipping.

Return Shipping Address: Please use the address provided in the RMA/return instructions, as it may differ from the initial shipping address.

Proposition 65 Warnings: cancer and reproductive harm www.p65warnings.ca.gov