Porsche has unveiled the 911 Flachbau RS, a one-off road-legal creation based on the 991.2-generation 911 GT2 RS. Built through Porsche’s Sonderwunsch programme, the special car revives the legendary slant-nose shape of the 935 while retaining the GT2 RS’s 700 PS twin-turbo engine.
The project combines Porsche’s motorsport heritage with bespoke engineering. It features a redesigned front end, a dramatic rear wing inspired by the 911 GT3 R Rennsport, extensive lightweighting and aerodynamic development carried out with Manthey.
Porsche 911 Flachbau RS
The most important detail is that this is not a new series-production 911 GT2 RS variant.
The Flachbau RS is a factory one-off created for a Porsche customer. The starting point was a like-new 2018 Porsche 911 GT2 RS with the Weissach Package, internally known as the 991.2 generation.
Porsche’s Sonderwunsch department spent almost three years developing the car with teams from Style Porsche, Weissach, Porsche Motorsport and Manthey.
The result is a road-legal collector car that combines the mechanical foundation of the GT2 RS with bespoke bodywork and motorsport-inspired aerodynamic changes.
Key Highlights
- One-off factory Sonderwunsch creation
- Based on the 2018 991.2 Porsche 911 GT2 RS Weissach
- 700 PS 3.8-litre twin-turbo flat-six
- Rear-wheel drive and 7-speed PDK
- Flachbau/slant-nose body design
- Styling inspired by the Porsche 935/78 “Moby Dick”
- 31.6 kg additional weight reduction
- Manthey aerodynamic components
- New GT3 R Rennsport-inspired rear wing
- European road homologation
- Extensive Nürburgring and wind-tunnel testing
935 Moby Dick Inspiration
The visual inspiration comes from one of Porsche’s most famous racing cars, the 935/78 “Moby Dick”.
The 935 originated in 1976 from the 930-generation 911 Turbo and became one of Porsche’s most successful endurance racers. Its elongated 935/78 body earned the famous “Moby Dick” nickname.
The new Flachbau RS interprets that shape for a modern road-going 911. Its flatter front wings, narrow stacked LED lighting and low-slung nose immediately distinguish it from a conventional GT2 RS.
The design also echoes Porsche’s historic Flachbau road cars. During the 1980s, Porsche offered a slant-nose version of the 930 Turbo, with 948 examples sold between 1982 and 1989.
700 PS GT2 RS Engine Remains Unchanged
Despite the dramatic visual transformation, Porsche did not increase the engine’s output.
The Flachbau RS retains the 3.8-litre six-cylinder twin-turbocharged boxer engine from the 991.2 GT2 RS. Porsche quotes 700 PS and 750 Nm for that powertrain, with power sent to the rear wheels through a seven-speed PDK transmission.
Porsche specifically says the drive system was left unchanged during the Sonderwunsch conversion.
That means the 700 PS figure belongs to the original GT2 RS powertrain rather than representing a newly developed engine for the Flachbau RS.
Porsche 911 Flachbau RS Specifications
| Specification | Details |
|---|---|
| Base model | 2018 Porsche 911 GT2 RS Weissach |
| Generation | 991.2 |
| Engine | 3.8-litre twin-turbo flat-six |
| Power | 700 PS |
| Torque | 750 Nm |
| Transmission | 7-speed PDK |
| Drive | Rear-wheel drive |
| Body style | Flachbau / slant-nose |
| Weight reduction | 31.6 kg |
| Status | Factory one-off |
| Road legality | Homologated for road use in Europe |
The original 991.2 GT2 RS was rated at 0-100 km/h in 2.8 seconds and a 340 km/h top speed. Those are GT2 RS figures, however, and Porsche has not announced separate acceleration or top-speed figures for the modified Flachbau RS.
Flachbau Design Gets a Modern Interpretation
The front of the car has been extensively redesigned.
The front wings sit lower than on the standard GT2 RS and feature slatted outlets designed to vent the wheel arches. The front bumper is also new, while Manthey aerodynamic elements add to the front-end treatment.
Instead of the familiar round 911 headlights, Porsche created a distinctive three-level LED lighting arrangement.
The slim units separately handle high beam, low beam and daytime running light functions, giving the Flachbau RS a much more aggressive appearance.
The car is finished in a special Grand Prix White shade with matte-black and exposed-carbon elements.
A U-shaped carbon-fibre graphic across the front references a design detail associated with the Martini-liveried 935/78 “Moby Dick”.
Huge Rear Wing Adds More Downforce
The rear wing is among the most dramatic parts of the Flachbau RS.
Its design is inspired by the wing used on the 992-generation 911 GT3 R Rennsport. Porsche says the Flachbau RS wing sits around five centimetres higher and uses distinctive S-shaped supports.
The wing can be manually fixed in three positions depending on the desired aerodynamic balance.
At 340 km/h in the High Downforce setting, Porsche says the Flachbau RS generates 554 kg of rear-axle downforce.
The car also receives a Manthey-based underbody package, rear diffuser and front splitter.
Carbon-fibre rear-wheel aerodiscs help reduce drag, while the overall aerodynamic package was validated through computational fluid dynamics, wind-tunnel work and real-world testing.
31.6 Kg Lighter Than the Donor Car
Porsche did more than change the bodywork.
The Sonderwunsch team removed or redesigned various components to reduce weight by 31.6 kg compared with the already lightweight GT2 RS Weissach donor car.
The interior demonstrates just how far the weight-saving approach went.
Lightweight Changes Include
- Porsche Communication Management system removed
- Audio equipment removed
- Large amounts of sound insulation removed
- Floor coverings reduced
- Unnecessary wiring removed
- Storage compartment replacing the PCM system
- Carbon-fibre components retained in key areas
- Racing-style exposed wiring and painted metal surfaces
The result is a much more spartan cabin than a conventional luxury-oriented 911.
The carbon-fibre bucket seats feature Flachbau RS embroidery, while a special dashboard plaque identifies the car as a “Factory One-Off 2026 | Flachbau RS.”
Extensive Nürburgring Testing
Creating a new body for an extreme road car required much more than styling work.
Porsche built three test vehicles and subjected the design to structural analysis, aerodynamic simulations, lighting tests, wind-tunnel validation and road testing.
The development programme also included 50 laps of the Nürburgring Nordschleife.
Porsche says endurance testing at Weissach simulated loads on the rear wing equivalent to approximately 150,000 kilometres of customer use.
The testing was particularly important because the Flachbau conversion changes the car’s aerodynamic surfaces significantly.
Porsche test driver Lars Kern said the car remained stable and precise at very high speeds during Nordschleife testing.
Is the Porsche 911 Flachbau RS a Production Model?
No. This is the most important fact to understand.
The Flachbau RS is a single factory-built Sonderwunsch car, created for an individual customer. It is not a new GT2 RS variant that buyers can order from Porsche dealerships.
Porsche’s use of the “Flachbau RS” name therefore should not be interpreted as the launch of a limited production series.
The project does, however, demonstrate what Porsche’s Sonderwunsch programme can achieve when a customer requests an extremely specialised interpretation of an existing model.
Confirmed vs Unconfirmed Information
| Information | Current Status |
| Flachbau RS exists | Confirmed |
| Factory Sonderwunsch one-off | Confirmed |
| Base car | Confirmed: 2018 991.2 GT2 RS Weissach |
| Engine output | Confirmed: 700 PS |
| Torque | Confirmed for GT2 RS engine: 750 Nm |
| 31.6 kg weight reduction | Confirmed |
| 554 kg rear-axle downforce at 340 km/h | Confirmed in High Downforce setting |
| 0-100 km/h | No separate Flachbau RS figure announced |
| Top speed | No separate figure announced; 340 km/h is the donor GT2 RS figure |
| Production numbers | One factory one-off |
| Road use | European road homologation confirmed |
This distinction prevents one of the easiest mistakes with the story: presenting the Flachbau RS as a brand-new 700 PS production Porsche.
It is instead an extensively reworked 991.2 GT2 RS that Porsche itself has transformed into a unique road-legal collector car.
Why the Flachbau RS Matters
The Flachbau RS is significant because it connects several chapters of Porsche history in one machine.
Its mechanical foundation comes from the 991.2 GT2 RS. Its silhouette references the 935, its name recalls the 1980s 930 Turbo Flachbau, and its modern rear wing draws inspiration from the 911 GT3 R Rennsport.
The project also revives a design language that has remained rare within Porsche’s modern production range.
Rather than simply adding retro styling, Porsche has integrated the slant-nose shape with modern aerodynamics, structural validation and road-legal requirements.
What Makes It Special?
- 935-inspired silhouette: A modern interpretation of the legendary Moby Dick racer.
- GT2 RS foundation: The car retains the 700 PS twin-turbo flat-six.
- Serious aerodynamics: Manthey components and a GT3 R Rennsport-inspired wing add functional downforce.
- Extreme exclusivity: Only one factory Sonderwunsch example exists.
- Track-developed: The conversion underwent extensive Nürburgring and wind-tunnel testing.
- Road legal: Porsche developed the car without sacrificing European road homologation.
Frequently Asked Questions
Is the Porsche 911 GT2 RS Flachbau a new production model?
No. The Flachbau RS is a one-off factory Sonderwunsch creation based on a 2018 Porsche 911 GT2 RS Weissach.
How much power does the Porsche Flachbau RS produce?
It retains the GT2 RS’s 3.8-litre twin-turbo flat-six, producing 700 PS and 750 Nm. Porsche did not modify the powertrain for the Flachbau conversion.
What is special about the Flachbau RS?
Its biggest distinction is the combination of a 935-inspired slant-nose body, modern Porsche Motorsport-style aerodynamics, extensive lightweighting and the GT2 RS powertrain in a single road-legal factory one-off.
Final Verdict
The Porsche 911 Flachbau RS is less a new model and more a showcase of what happens when Porsche’s heritage, motorsport engineering and Sonderwunsch personalisation programmes converge.
Its 700 PS engine is familiar from the 991.2 GT2 RS, but the redesigned body, 31.6 kg weight reduction, extreme aerodynamic package and 935 “Moby Dick” inspiration make this one-off substantially more distinctive than a standard GT2 RS.
For collectors, the appeal is obvious: this is a factory-created Porsche that revives one of the brand’s most recognisable racing silhouettes while remaining road legal. For everyone else, it is a fascinating glimpse at just how far Porsche can take a bespoke 911 project.