Exhaust› Mufflers and Resonators

Grail

Valved Rear Muffler System

$4,916.00

SKU: GR-21CAYMANGT4

Special Order
Special Order
Ships in 4–6 weeks
Free Shipping over $200
$100 Minimum Order
30 Days Return
INSTALL DIFFICULTY
DIY PRO SHOP

Moderate — 2–4 hours

Overview

The Grail GR-21CAYMANGT4 is a valved rear muffler system designed for the Porsche 718 Cayman GT4. This exhaust system features ECE approval, ensuring it can be used on EU vehicles without registration. It includes dual or optional none tailpipes.
Show original supplier description
The Grail GR-21CAYMANGT4 is an ECE-approved valved exhaust system specifically engineered for the Porsche 718 Cayman GT4. This system includes a valved rear muffler and offers the option of dual tailpipes. The valved design allows for adjustable sound profiles, providing a sharper sound when desired. According to available information, Grail exhaust systems for the Porsche 718 Cayman GT4 are approximately 3kg lighter than the OEM system, and the OPFs (Otto Particulate Filters) remain installed, ensuring compliance and emissions standards are met. Installation instructions are typically not included, and professional installation may be recommended.

Product descriptions are provided by our supplier partners and may not always be perfectly accurate. Not sure this fits? or call (760) 282-4645 and we’ll verify before you order.

Fitment

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Specifications

BrandGrail
Part NumberGR-21CAYMANGT4
CategoryExhaust
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Returns & Fitment

Built for enthusiasts. Every order is backed by our 30 day return window on eligible items. Unused and uninstalled products may be returned with approved RMA and no restocking fees when received in new condition. Orders placed through the MOTORMIA app with a complete build qualify for our Fitment Guarantee — free return shipping if the part doesn’t fit your exact setup. The guarantee covers fit only; installation must follow manufacturer instructions, and we recommend a qualified shop for parts marked Difficulty 4–5.

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Shipping

Orders are processed in 1–3 business days. In stock parts ship promptly from our partner network. Special-order items either aren’t currently stocked or are built to your spec — expect 4–6 weeks. If a part goes on backorder while your order is in the queue, we’ll reach out and work through discounted alternatives together.

Free shipping over $200 in the continental US. Alaska, Hawaii, U.S. territories (Puerto Rico, U.S. Virgin Islands, Guam, American Samoa, and the Northern Mariana Islands), and international orders carry surcharges — most appear at checkout. Some exceptions (LTL freight, or suppliers who quote freight only after we place the order) won’t. In those cases we’ll reach out with the exact charge before your order moves forward.

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