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Fabspeed Side Muffler Bypass Pipes Porsche 991 GT3 / GT3 RS (2014-2019)

SKU: FS.POR.991GT3.SMB
Price
$1,508.95

Select Valve Configuration:

Non-Valved
Currently Backordered - You can still place your order and we'll ship your order as soon as the product is back in stock!

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Installation Services

Don’t worry about the hassle — let our expert team at Forza Motorworks handle the installation for you. Our professional installation ensures everything fits and operates exactly as intended, giving you clean, factory-quality results, proper wiring or mounting, and avoiding the risks of DIY mistakes. You’ll save time, avoid frustration, and get peace of mind knowing the job is done right the first time. Contact us to learn about our installation services and enjoy a seamless upgrade from day one.

FAQ

Shipping Information
For items that are in stock, purchases made after 9am EST will be usually be shipped out in the next 1-2 business days. Please inquire to confirm lead times if you have specific time constraints. Orders will be sent via signature required at our discretion unless otherwise requested. 

International Shipping
Any and all customs duties, taxes, import fees, and/or tariffs assessed in connection with the purchase shall be the sole responsibility of the customer/end user.

Cancellations / Returns

Original sales receipt or order number must accompany all return requests.

Forza Motor Works accepts returns for exchange, store credit, or refund within fourteen (14) calendar days of the delivery date, subject to the terms and conditions below. After fourteen (14) calendar days, all sales are final unless otherwise approved in writing by Forza Motor Works.

To be eligible for return, products must be in new, unused, unaltered, and resalable condition, including all original packaging, instructions, hardware, documentation, and accessories. Returned items must not show any signs of installation, use, wear, damage, modification, painting, coating, or alteration of any kind.

The following items are non-returnable and non-refundable:

• Special-order products
• Custom-built or made-to-order products
• Products manufactured to customer specifications
• Custom color or finish products
• Manufacturer-direct-shipped products designated as non-returnable
• Products with extended lead times, including but not limited to headers, exhaust systems, wheels, and other special-order performance products
• Any item specifically identified on the product page as non-returnable

Orders for special-order, custom-built, made-to-order, vehicle-specific, or manufacturer-direct-shipped products may not be canceled once the order has been submitted to the manufacturer.

If an item is received damaged during shipping or was shipped incorrectly by Forza Motor Works, Customer Support must be contacted within forty-eight (48) hours of delivery. Claims for shipping damage must include clear photographs of the product, packaging, shipping box, and shipping label at the time of unpacking.

Products determined by Forza Motor Works to have been incorrectly shipped may qualify for replacement, store credit, or refund at our sole discretion. Manufacturer defects are subject to the applicable manufacturer's warranty policies and procedures. Forza Motor Works does not provide any separate product warranty unless expressly stated in writing.

All returns must be authorized prior to shipment and must be assigned a Return Merchandise Authorization (RMA) number. The RMA number must be clearly displayed on the outside of the return package. Returns received without an authorized RMA number may be refused or denied credit.

To obtain a Return Merchandise Authorization (RMA), please contact:

Forza Motor Works
Email: info@forzamotorworks.com

All refunds, exchanges, and store credits are contingent upon inspection and approval of the returned merchandise. Forza Motor Works reserves the right to deny any return that does not comply with this policy.

Approved returns may be subject to a restocking fee of up to twenty five percent (25%) of the purchase price. Original shipping charges are non-refundable. Customer is responsible for all return shipping costs unless the return is the direct result of an error made by Forza Motor Works.

FITMENT, INSTALLATION & PRODUCT USE

Customer is responsible for verifying vehicle compatibility, fitment, and intended use prior to installation. While Forza Motor Works makes reasonable efforts to provide accurate product information and fitment guidance, final responsibility for compatibility rests solely with the customer.

Products that have been installed, test-fitted, modified, painted, coated, damaged, or otherwise used are not eligible for return.

Many aftermarket performance products are intended for off-road, racing, or competition use only and may not be legal for use on public roads in all jurisdictions. Customer is solely responsible for determining compliance with all applicable federal, state, and local laws and regulations.

LIMITATION OF LIABILITY

FORZA MOTOR WORKS SHALL NOT BE LIABLE FOR ANY INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, PUNITIVE, OR CONSEQUENTIAL DAMAGES ARISING FROM THE PURCHASE, INSTALLATION, USE, MISUSE, FAILURE, OR INABILITY TO USE ANY PRODUCT SOLD BY FORZA MOTOR WORKS.

FORZA MOTOR WORKS SHALL NOT BE RESPONSIBLE FOR LOSS OF TIME, LOSS OF REVENUE, LOSS OF PROFITS, LOSS OF VEHICLE USE, TOWING CHARGES, RENTAL VEHICLE COSTS, STORAGE FEES, DIAGNOSTIC FEES, INSTALLATION COSTS, REMOVAL COSTS, ALIGNMENT CHARGES, TUNING FEES, SHIPPING EXPENSES, FINES, PENALTIES, PROPERTY DAMAGE, VEHICLE DAMAGE, OR ANY OTHER INCIDENTAL OR CONSEQUENTIAL LOSS OR EXPENSE.

TO THE MAXIMUM EXTENT PERMITTED BY LAW, FORZA MOTOR WORKS' TOTAL LIABILITY FOR ANY CLAIM ARISING FROM THE PURCHASE OR USE OF A PRODUCT SHALL NOT EXCEED THE AMOUNT PAID FOR THE SPECIFIC PRODUCT GIVING RISE TO THE CLAIM.

By placing an order with Forza Motor Works, the customer acknowledges and agrees to all terms and conditions contained herein, including all return, exchange, warranty, and limitation-of-liability provisions.

Product Description

 

 

The FABSPEED Side Muffler Bypass Pipes for the 991 GT3 / GT3 RS (2014–2016) ditch the heavy, restrictive factory side mufflers to unlock freer exhaust flow, sharper throttle response, and a raw, aggressive “track-ready” exhaust tone. Engineered for maximum flow, they drop substantial weight from the rear end and transform the exhaust note into an exotic CUP-car-like wail — ideal for track days, spirited drives, or a full performance build. Built from mandrel-bent T304 stainless steel with precision-built valved piping, this kit gives your GT3 a more visceral exhaust personality without sacrificing reliability or quality.

Fitment Notes

  • Fits Porsche 911 (991) GT3 and GT3 RS for model years 2014–2019. 

  • Designed as a direct bolt-on replacement for factory side mufflers — no cutting or welding required. 

  • Includes high-quality valves from Helical — retains exhaust-valve control for variable tone depending on driving conditions. 

  • Includes relocated O₂ sensor bungs to ensure factory-like sensor readings even if paired with aftermarket headers.

  • Best suited for track-oriented builds or aggressive street/spirited driving; when paired with long-tube headers, these bypass pipes maximize exhaust flow.

Included

  • Left and right side muffler bypass pipe assemblies (valved or non-valved version) fabricated in T304 stainless steel. 

  • O₂ sensor ports (bungs) for compatibility with factory or aftermarket sensor placement. 

  • All required mounting hardware and gaskets for a bolt-on installation — utilizes factory mounting points and exhaust hangers.

  • Exhaust valves (Helical brand) with pneumatic actuator for controlled opening/closing depending on driving mode.

Product Specs

  • Construction: 14-16 gauge T304 stainless steel, mandrel-bent for smooth flow and strength.

  • Weight Savings: Approximately –34 lbs compared to the factory side muffler assemblies.

  • Flow Configuration: Valved bypass — valves open under performance conditions for unrestricted flow; valves close to tame sound when desired. 

  • Sound Character: Aggressive, exotic exhaust note emulating track-cup cars of Porsche’s racing lineage.

  • Finish: Brushed stainless steel as standard; able to handle high exhaust temps and resist corrosion under stress.

Product Features

  • Significant Weight Reduction — Shedding 34 lbs from the rear end improves overall handling, throttle response, and reduces unsprung/rear mass.

  • Aggressive Cup-Car Sound — Without restrictive mufflers, the exhaust delivers an exotic, high-pitched flat-six scream under throttle and revs.

  • Valved Flexibility — Helical valves allow you to control exhaust tone dynamically, balancing street usability and track aggression.

  • OEM-Compatible Sensor Setup — O₂ bungs keep factory or aftermarket sensors functional, even with modified exhaust flow.

  • Full-Flow Exhaust Path — When combined with race headers, this bypass kit enables maximum flow for peak engine performance.

  • Bolt-On Installation — Uses factory mounting points and hardware for a clean install, no fabrication required.

  • Durable, Track-Ready Construction — T304 stainless steel with mandrel bends and quality valve actuation ensures longevity under heat and load.