The SOUL Long Tube Street Headers are designed specifically for the 3.8L naturally aspirated flat-six found in the Porsche 981 Cayman GT4, Boxster Spyder, and GT4 Clubsport. By replacing the restrictive factory header assemblies with properly sized long-tube runners, performance-oriented collectors, and large-diameter free-flowing catalytic converters, the system improves exhaust flow, throttle response, power delivery, and flat-six exhaust character while retaining a catted configuration.
SOUL developed this application specifically around the airflow requirements of the 3.8L engine, using 2-inch primary runners and appropriately sized collectors to support strong performance throughout the rev range and during sustained high-RPM operation. The catalytic converters are also sized to provide the flow capacity and durability required for demanding street and track use.
Third-party testing performed on a Dyno Dynamics dynamometer demonstrated significant gains when the headers were combined with ECU calibration. SOUL reports approximately 30 wheel horsepower gained with the headers and tune together, with approximately 12 wheel horsepower attributed to the Street Headers after the tune had already been applied. Actual results will vary depending on vehicle condition, fuel, calibration, environmental conditions, and supporting modifications.
For owners who want improved exhaust flow, throttle response, and naturally aspirated flat-six sound without moving to a fully catless configuration, the SOUL Long Tube Street Headers provide a strong balance of performance and street usability.
Fits 2015–2016 Porsche 981 Cayman GT4, Boxster Spyder, and GT4 Clubsport
Designed specifically around the 3.8L naturally aspirated flat-six
Long-tube header architecture developed specifically for the 981 GT4 / Spyder / Clubsport platform
Features 2-inch primary runners
Properly sized collectors are designed to optimize exhaust flow and support sustained high-RPM operation
Large-diameter, free-flowing catalytic converters provide increased exhaust flow while retaining a catted configuration
Designed to increase power, throttle response, and naturally aspirated flat-six exhaust character
Designed by SOUL to provide additional performance without triggering a check engine light
Third-party Dyno Dynamics testing demonstrated approximately 30 whp gained with the headers and ECU calibration combined
Testing demonstrated approximately 12 whp gained from the Street Headers after the ECU tune had already been applied
Port-matched flanges provide a smooth transition from the cylinder head into the primary runners
Smooth-radius primary tubing helps reduce unnecessary exhaust restriction
Performance-oriented collectors optimize the transition from the individual primary runners into the remainder of the exhaust system
Constructed from T304L stainless steel
Each header assembly is rigorously quality-checked in-house
Direct bolt-on installation
Each set is fixture-tested prior to shipment to help ensure accurate fitment
Detailed installation instructions included
Backed by SOUL Performance Products' Lifetime Warranty for both street and track use
The SOUL Long Tube Street Headers are designed as a direct bolt-on upgrade and to provide increased exhaust flow and performance without triggering a check engine light.
Third-party Dyno Dynamics testing demonstrates that the 3.8L engine can benefit substantially when the increased exhaust flow is combined with an appropriate ECU calibration. Testing showed approximately 30 additional wheel horsepower with the headers and tune combined, while comparison testing indicated approximately 12 wheel horsepower of that improvement came from the Street Headers after the ECU tune had already been installed.
An ECU tune is not included with the headers, and actual power gains will vary depending on vehicle condition, fuel quality, calibration, environmental conditions, and additional modifications.
The SOUL Long Tube Street Headers retain large-diameter, free-flowing catalytic converters while significantly improving the exhaust path compared with the factory header assemblies.
This configuration is intended for owners who want increased flow, response, performance, and exhaust character while retaining catalytic converters rather than converting the vehicle to a fully catless exhaust configuration.
These headers retain catalytic converters; however, the product is not CARB certified and may not be legal for use on emissions-controlled vehicles. SOUL identifies this product as intended for off-road use only.
Customers are responsible for ensuring compliance with all applicable local, state, and federal regulations before installation or use.
The SOUL Long Tube Street Headers are designed specifically for the 3.8L naturally aspirated flat-six found in the Porsche 981 Cayman GT4, Boxster Spyder, and GT4 Clubsport. By replacing the restrictive factory header assemblies with properly sized long-tube runners, performance-oriented collectors, and large-diameter free-flowing catalytic converters, the system improves exhaust flow, throttle response, power delivery, and flat-six exhaust character while retaining a catted configuration.
SOUL developed this application specifically around the airflow requirements of the 3.8L engine, using 2-inch primary runners and appropriately sized collectors to support strong performance throughout the rev range and during sustained high-RPM operation. The catalytic converters are also sized to provide the flow capacity and durability required for demanding street and track use.
Third-party testing performed on a Dyno Dynamics dynamometer demonstrated significant gains when the headers were combined with ECU calibration. SOUL reports approximately 30 wheel horsepower gained with the headers and tune together, with approximately 12 wheel horsepower attributed to the Street Headers after the tune had already been applied. Actual results will vary depending on vehicle condition, fuel, calibration, environmental conditions, and supporting modifications.
For owners who want improved exhaust flow, throttle response, and naturally aspirated flat-six sound without moving to a fully catless configuration, the SOUL Long Tube Street Headers provide a strong balance of performance and street usability.
Fits 2015–2016 Porsche 981 Cayman GT4, Boxster Spyder, and GT4 Clubsport
Designed specifically around the 3.8L naturally aspirated flat-six
Long-tube header architecture developed specifically for the 981 GT4 / Spyder / Clubsport platform
Features 2-inch primary runners
Properly sized collectors are designed to optimize exhaust flow and support sustained high-RPM operation
Large-diameter, free-flowing catalytic converters provide increased exhaust flow while retaining a catted configuration
Designed to increase power, throttle response, and naturally aspirated flat-six exhaust character
Designed by SOUL to provide additional performance without triggering a check engine light
Third-party Dyno Dynamics testing demonstrated approximately 30 whp gained with the headers and ECU calibration combined
Testing demonstrated approximately 12 whp gained from the Street Headers after the ECU tune had already been applied
Port-matched flanges provide a smooth transition from the cylinder head into the primary runners
Smooth-radius primary tubing helps reduce unnecessary exhaust restriction
Performance-oriented collectors optimize the transition from the individual primary runners into the remainder of the exhaust system
Constructed from T304L stainless steel
Each header assembly is rigorously quality-checked in-house
Direct bolt-on installation
Each set is fixture-tested prior to shipment to help ensure accurate fitment
Detailed installation instructions included
Backed by SOUL Performance Products' Lifetime Warranty for both street and track use
The SOUL Long Tube Street Headers are designed as a direct bolt-on upgrade and to provide increased exhaust flow and performance without triggering a check engine light.
Third-party Dyno Dynamics testing demonstrates that the 3.8L engine can benefit substantially when the increased exhaust flow is combined with an appropriate ECU calibration. Testing showed approximately 30 additional wheel horsepower with the headers and tune combined, while comparison testing indicated approximately 12 wheel horsepower of that improvement came from the Street Headers after the ECU tune had already been installed.
An ECU tune is not included with the headers, and actual power gains will vary depending on vehicle condition, fuel quality, calibration, environmental conditions, and additional modifications.
The SOUL Long Tube Street Headers retain large-diameter, free-flowing catalytic converters while significantly improving the exhaust path compared with the factory header assemblies.
This configuration is intended for owners who want increased flow, response, performance, and exhaust character while retaining catalytic converters rather than converting the vehicle to a fully catless exhaust configuration.
These headers retain catalytic converters; however, the product is not CARB certified and may not be legal for use on emissions-controlled vehicles. SOUL identifies this product as intended for off-road use only.
Customers are responsible for ensuring compliance with all applicable local, state, and federal regulations before installation or use.
