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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.

Return Policy
We have a 30-day return policy, which means you have 30 days after receiving your item to request a return. To be eligible for a return, your item must be in the same condition that you received it, unused and in its original packaging. All returns are subject to a restocking fee based on item and package condition. Buyer is responsible for paying for return shipping costs. If you need a return label, we will email you a return label and deduct cost from refund. Original shipping costs are not refundable. Special order items are not eligible for return.

Cancellation Policy
In order to cancel your order you must email within 24 hours of placing your order or before your order has shipped, whichever occurs first. Special order items are not eligible for cancelation.

Exchange Policy
We have a 30-day exchange policy, which means you have 30 days after receiving your item to request an exchange. To be eligible for an exchange, your item must be brand new in box. Buyer is responsible for paying all shipping costs to exchange product.

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.