SOUL Performance Products

The SOUL Performance Competition Headers are precision-engineered aftermarket exhaust manifolds developed for the Porsche 718 Cayman GT4 RS and 718 Spyder RS, featuring Porsche's naturally aspirated 4.0-litre flat-six engine.

Fits:

• Porsche Boxster Spyder RS 718 4.0L 01/2019>>
• Porsche Cayman GT4 RS 718 4.0L  

Designed for performance-focused owners and motorsport applications, these Competition Headers replace the original exhaust manifold assemblies and integrated primary catalytic converters with a lightweight, freer-flowing stainless steel design.

The factory exhaust system must balance engine performance with emissions regulations, noise requirements and vehicle packaging constraints. These considerations influence the shape, length and diameter of the original exhaust headers.

SOUL Performance developed its Competition Headers to maximise the available space around the engine, using longer exhaust runners and enlarged merge collectors to improve exhaust gas movement.

Unlike the standard Porsche 718 GT4, for which SOUL offers both catted and catalyst-free header options, the manufacturer has chosen a catalyst-free-only header design for the GT4 RS and Spyder RS.

This allows the available space to be used for longer tubing and collectors designed to connect smoothly to the downstream 3-inch over-axle exhaust flow path.

The headers are manufactured in the USA from mandrel-bent T304L stainless steel with a 0.065-inch wall thickness.

Each set features back-purged TIG welding using high-purity argon shielding gas to support strong, consistent weld construction and long-term durability.

Precision-cast cylinder-head flanges provide a smooth transition between the engine's exhaust ports and the primary runners.

The connecting exhaust flanges are waterjet-cut to tight dimensional tolerances, helping maintain consistent alignment and accurate installation.

SOUL also uses dedicated aluminium welding fixtures to minimise distortion during fabrication.

These construction methods make the Competition Headers suitable for demanding operating conditions involving repeated heating, cooling and vibration.

What This Product Does:
The exhaust headers are responsible for collecting hot combustion gases leaving the engine's cylinder heads and directing them into the downstream exhaust system.

During engine operation, the exhaust valves open and release combustion gases from each cylinder.

These gases travel through the individual header runners before joining at the collectors and continuing towards the over-axle pipes and rear exhaust.

The shape, length and cross-sectional area of the runners influence exhaust pulse movement, flow resistance and engine performance characteristics.

The SOUL Competition Headers are designed to optimise this process.

Their main functions include:

1. Collecting Exhaust Gases

The headers gather exhaust gases from the engine's cylinder-head exhaust ports and direct them into the downstream exhaust system.

2. Improving Exhaust Gas Flow

The longer runners and enlarged merge collectors provide a smoother, less restrictive path for exhaust gases.

This is intended to support efficient engine breathing.

3. Supporting Exhaust Scavenging

Exhaust gases move through the headers as pressure pulses.

Carefully designed runner and collector geometry can improve pulse interaction and help the engine expel combustion gases more effectively.

4. Reducing Exhaust Restriction

The Competition Headers remove the factory primary catalytic converters.

This reduces a significant source of flow resistance in the original header assemblies.

5. Enhancing Engine Responsiveness

Improved exhaust gas movement may help the engine respond more readily to accelerator input.

The effect will depend on the complete exhaust system and vehicle configuration.

6. Supporting Performance Potential

A freer-flowing exhaust system can help the naturally aspirated flat-six engine operate more efficiently during demanding driving conditions.

7. Enhancing Exhaust Sound

The catalyst-free construction and revised runner design provide a more pronounced exhaust note.

This allows the distinctive high-revving character of the 4.0-litre engine to become more apparent.

8. Reducing Exhaust Weight

The headers offer a manufacturer-reported saving of approximately 4.5 lb compared with the original assemblies.

9. Providing Durable Exhaust Construction

T304L stainless steel, precision flanges and back-purged TIG welding help withstand high temperatures and repeated thermal cycling.

10. Connecting with Factory or Upgraded Exhaust Components

The headers are designed to bolt to compatible original or aftermarket over-axle pipes.

They are developed to work with the 3-inch flow path of SOUL's performance over-axle exhaust components.



Why Upgrading Matters:

1. Improved Exhaust Flow

The Competition Headers use longer primary runners and enlarged merge collectors to provide a more efficient path for exhaust gases.

This supports improved engine breathing and reduces unnecessary restriction.

2. Enhanced Performance Potential

The design is intended to improve exhaust efficiency and engine response.

SOUL states that the headers deliver increases in sound, power and responsiveness, although no universal numerical gains are established for this component alone.

3. More Responsive Engine Behaviour

A less restrictive exhaust path may improve the engine's response during acceleration.

This can contribute to a more engaging driving experience.

4. Increased Flat-Six Exhaust Character

The 4.0-litre engine is renowned for its distinctive high-revving sound.

The Competition Headers allow more of this exhaust character to pass through the system, producing a stronger and more aggressive soundtrack.

5. Lightweight Design

SOUL's Competition Headers are approximately 4.5 lb lighter than the original factory assemblies.

This reduces unnecessary weight while retaining robust stainless steel construction.

6. Precision-Engineered Fitment

The cast cylinder-head flanges, accurately cut connection flanges and dedicated welding fixtures are intended to maintain consistent fitment.

Accurate flange alignment is important for preventing leaks and unnecessary mechanical stress.

7. Durable T304L Stainless Steel

The stainless steel construction provides corrosion resistance and durability under demanding exhaust temperatures.

8. High-Quality Welding

Back-purged TIG welding supports consistent weld penetration and helps maintain the durability of the header assemblies.

9. Compatible Exhaust Upgrades

The Competition Headers can be combined with factory or suitable upgraded over-axle pipes.

This allows owners to develop their exhaust configuration in stages.

10. Direct Bolt-On Installation

The headers are designed to fit the appropriate factory mounting locations without requiring fabrication under normal installation conditions.

11. Motorsport-Focused Construction

The combination of stainless steel tubing, precision flanges and high-quality welding makes the product suitable for demanding performance applications.

12. Manufacturer Lifetime Warranty

SOUL Performance provides a lifetime warranty for its exhaust components, subject to the manufacturer's published terms and conditions.

The SOUL Performance Competition Over-Axle Pipes are premium aftermarket performance exhaust components specifically designed for the Porsche 718 Cayman GT4 RS and 718 Spyder RS.

Fits:

• Porsche Boxster Spyder RS 718 4.0L 01/2019>>
• Porsche Cayman GT4 RS 718 4.0L  

Developed for Porsche's naturally aspirated 4.0-litre GT3-derived flat-six engine, these precision-engineered pipes replace the factory over-axle exhaust sections with a lighter, freer-flowing stainless steel configuration.

The original Porsche over-axle pipes incorporate secondary catalytic converters and particulate-filter housings. These components form part of the original exhaust configuration, which is designed around emissions requirements, packaging constraints and noise control.

SOUL Performance developed its Competition Over-Axle Pipes to eliminate these restrictions and improve the movement of exhaust gases through the system.

Unlike traditional round-tube exhaust replacements, the SOUL design uses specially shaped oval tubing to maintain a full 3-inch flow diameter throughout the pipework while providing sufficient clearance around the vehicle's suspension and body components.

This design allows a larger exhaust flow path to be accommodated within the limited space available above the rear axles.

The Competition Over-Axle Pipes are manufactured from mandrel-bent T304L stainless steel with a 0.065-inch wall thickness, providing strength, corrosion resistance and durability under repeated high-temperature operation.

What This Product Does:
The over-axle pipes form part of the exhaust system between the exhaust headers and the rear exhaust assembly.

Their primary function is to carry hot combustion gases from the engine's upstream exhaust components towards the rear silencers and tailpipes.

The SOUL Competition Over-Axle Pipes perform this function while providing a larger and less restrictive exhaust gas passage.

1. Direct Exhaust Gases

The pipes transport exhaust gases from the header outlets towards the rear exhaust system.

They form an essential connection between the engine's exhaust manifolds and the rear silencers.

2. Improve Exhaust Gas Flow

The full 3-inch flow path is designed to minimise unnecessary restrictions.

This allows exhaust gases to travel more freely through the over-axle sections.

3. Eliminate Secondary Catalytic Converter Restrictions

The Competition Over-Axle Pipes remove the factory secondary catalytic converters from this part of the system.

This reduces exhaust flow restriction but also removes part of the original emissions-control equipment.

4. Replace Particulate-Filter Housings

The original over-axle assemblies incorporate particulate-filter housings.

Their contents and monitoring arrangements vary according to vehicle market.

SOUL removes these housings entirely with its replacement pipes.

5. Enhance Exhaust Sound

Removing the original internal exhaust restrictions allows more of the engine's exhaust pulses and sound to travel into the rear exhaust.

The result is a noticeably louder and more aggressive flat-six soundtrack.

6. Support Engine Responsiveness

More efficient exhaust flow may help the engine respond more readily to accelerator input, particularly during high-load and high-RPM operation.

Actual performance changes depend on the vehicle's complete exhaust configuration and operating conditions.

7. Reduce Exhaust Weight

The replacement pipes provide a manufacturer-reported reduction of approximately 13.3 lb compared with the original assemblies.

8. Maintain Suspension Clearance

The specially developed oval tubing allows a large flow area to pass through the restricted space above the rear axles.

This design helps maintain clearance around the suspension and body components.

9. Reduce Heat-Retaining Exhaust Mass

Eliminating the original catalyst and filter housings reduces the amount of bulky exhaust material within the over-axle area.

Appropriate thermal management remains necessary.

10. Connect Factory or Performance Exhaust Components

The pipes allow compatible factory and aftermarket headers and rear exhaust systems to be joined through a performance-focused over-axle arrangement.

Why Upgrading Matters:

1. Improved Exhaust Gas Flow

The full 3-inch exhaust flow path provides a less restrictive route for gases travelling between the headers and rear exhaust.

This supports improved exhaust efficiency.

2. Significant Exhaust Sound Enhancement

The Competition Over-Axle Pipes are designed to produce one of the most substantial exhaust sound changes available from a single component.

They allow more of the Porsche 4.0-litre flat-six engine's character to be heard.

3. Reduced Exhaust Restriction

Removing the factory secondary catalytic converters and filter housings reduces internal restrictions.

This allows exhaust gases to travel more directly towards the rear exhaust.

4. Reduced Exhaust Weight

SOUL reports a saving of approximately 13.3 lb (6 kg) compared with the original over-axle pipe assemblies.

Reducing unnecessary weight is beneficial in performance-focused vehicle preparation.

5. Motorsport-Focused Construction

The mandrel-bent stainless steel tubing, precise flanges and high-quality welding are designed for demanding operating conditions.

6. Enhanced Engine Responsiveness

Improved exhaust flow may support sharper engine response and more effective high-RPM operation.

No universal numerical horsepower or torque improvement is guaranteed for these pipes alone.

7. Optimised Pipe Geometry

The specially developed oval sections allow SOUL to maintain a large exhaust flow area while accommodating the restricted packaging space above the rear axles.

8. Durable Stainless Steel

T304L stainless steel provides corrosion resistance and durability under repeated high-temperature operation.

9. Reduced Factory Exhaust Heat Retention

The simpler pipework eliminates bulky factory catalyst and filter housings.

However, SOUL strongly recommends thermal wrapping or another suitable heat management solution.

10. Compatible with Other Exhaust Upgrades

The pipes are designed to work with compatible factory or upgraded headers and rear exhaust systems.

This makes them suitable for a range of performance exhaust configurations.

11. Precision-Manufactured Fitment

Waterjet-cut flanges and dedicated fabrication fixtures support accurate installation and consistent component alignment.

12. Direct Bolt-On Installation

The pipes are designed to replace the corresponding original over-axle assemblies without fabrication when fitted to a compatible vehicle.

13. Manufacturer Lifetime Warranty

SOUL Performance provides a lifetime warranty for its exhaust components, subject to the published warranty conditions.

NOTE: In the United Kingdom, sports catalytic converters and bypass pipes do not have type approval and are not legally permitted for use on vehicles manufactured after 1st March 2001. They are not MOT compliant and cannot be used on public roads. These components are intended solely for race and track use.

For vehicles manufactured before 1st March 2001, a non-type approved sports catalytic converter may be fitted, provided it offers comparable performance to the original and the vehicle continues to meet the applicable emissions standards for its age. The vehicle must still pass an MOT test.

If you are located outside the UK, please check your local laws and regulations to ensure compliance.