The Porsche 982 platform is celebrated for its balance of precision handling and naturally aspirated flat-six character, but many owners find that modern emissions regulations have dulled some of that excitement. Since 2018, particulate filters have been fitted across Europe and other markets, muting the distinctive tone that makes the Cayman GT4 and Boxster GTS 4.0 so engaging. Milltek recognized this issue and engineered a series of exhaust upgrades designed to bring back the edge, making the car sound and feel like a proper Porsche should.
Milltek Sport’s Valved Particulate-Filter-Back Exhaust System was developed specifically for the 982 Cayman GT4 produced before February 2020. This setup addresses the acoustic limitations caused by the factory gasoline particulate filter, restoring a full-bodied tone while maintaining everyday refinement when needed.
With valves closed, the exhaust delivers a subtle burble suitable for urban driving. When opened, it releases an aggressive flat-six wail that feels more at home on the track than the boulevard. The inclusion of dual valve assemblies, a rear silencer, and 4.5-inch GT-style tips in polished or Cerakote black ensures both performance and visual impact. A 60.5mm (2.375-inch) pipe diameter balances improved flow with compatibility, meaning the system integrates cleanly without compromising drivability.
The result is a noticeable transformation that reconnects drivers to the mechanical heartbeat of the Cayman GT4. By eliminating the muffled, restrained note of the stock system, Milltek’s filter-back exhaust restores confidence and character every time the throttle is pressed.
For enthusiasts who demand even more performance from their Porsche 718 Cayman GT4 exhaust setup, Milltek’s GPF/OPF Bypass Pipes take things further. These 70mm (2.75-inch) stainless pipes completely bypass the restrictive particulate filters, unlocking both horsepower and torque while producing a sharper, motorsport-inspired soundtrack.
The bypass pipes are compatible with both manual and PDK-equipped vehicles built before and after February 2020. Fitment covers the Cayman GT4 as well as the Boxster GTS 4.0, with seamless integration alongside factory or Milltek filter-back systems. Because the removal of particulate filters alters the vehicle’s operating conditions, a Stage 2 ECU remap is required. Once paired with tuning, the improvement in throttle response and overall urgency is undeniable.
Drivers who make the jump to bypass pipes describe the difference as night and day. Not only is the car louder and more visceral, but the performance gains give the flat-six a liveliness that factory hardware cannot match. For track use and spirited canyon runs, it is the ultimate expression of what a naturally aspirated Porsche should feel like.
What sets Milltek apart is its ability to design systems that balance quality, performance, and aesthetics. Every component is crafted from premium materials with precise fitment in mind, ensuring longevity and reliability. The large GT-style tips not only project the aggressive sound but also provide a motorsport-inspired look that enhances the Cayman and Boxster’s rear profile.
Together, the valved particulate-filter-back system and GPF/OPF bypass pipes form a range of solutions that cater to different levels of enthusiasm. Whether the goal is to sharpen the soundtrack without deleting emissions equipment or to achieve maximum performance with full bypass hardware, Milltek has engineered an option to meet that need. Both routes restore the visceral connection between driver and machine that makes Porsche ownership special.
Milltek’s exhaust upgrades for the 982 Cayman GT4 and Boxster GTS 4.0 are available now through Bulletproof Automotive. As a trusted source for high-end aftermarket components, Bulletproof ensures Porsche enthusiasts have access to the very best performance parts to transform their cars both on the street and the track.
