The Flachbau is one of the coolest chapters in Porsche’s history. Born from the company’s obsession with its 935 race car, the slant-nose 911 turned the already wild 930 Turbo into something that looked like it had escaped from a racetrack.
The name Flachbau translates roughly to ‘flatnose’, and the defining feature was, quite obviously, the nose. Instead of the familiar round headlights, the 911 got a much flatter front end inspired by the 935 race car. Later versions featured pop-up headlights, wider front wings and distinctive cooling vents, giving the 930 a completely different character. Porsche built just 948 examples between 1982 and 1989, making the Flachbau one of the rarest factory-built 911 variants of its era. Now, more than three decades later, the Flachbau is back. And this time, Porsche has given it the RS treatment.
Meet the 911 Flachbau RS, a one-off Sonderwunsch creation based on a 2018 991.2-generation 911 GT2 RS with the Weissach Package. It was commissioned by a Porsche enthusiast and developed over almost three years by Porsche’s Sonderwunsch department, Style Porsche, Weissach engineers, Porsche Motorsport and Manthey.
The idea was simple: take the extreme GT2 RS and give it a modern interpretation of the legendary 935-inspired Flachbau shape. The front end is completely different, with flatter front wings and bespoke headlights replacing the usual 911 face. The bonnet also gets a distinctive U-shaped graphic inspired by the 935/78 Le Mans racer, better known as Moby Dick.
The rear is even more dramatic. The Flachbau RS gets a huge rear wing with S-shaped mounts, inspired by the wing of the 911 GT3 R Rennsport. Manthey was involved in developing the aerodynamic package, while Porsche also carried out extensive testing in the wind tunnel and lighting tunnel to make sure the radical bodywork remained road legal.
Underneath, however, the mechanical recipe remains largely familiar. Porsche has kept the GT2 RS powertrain unchanged, meaning this Flachbau gets the 3.8-litre twin-turbocharged flat-six from the 991.2 GT2 RS. That means 691 bhp, rear-wheel drive and a seven-speed PDK gearbox. The donor car was already one of the most serious 911s Porsche had ever built, so there was hardly any need to mess with the engine. Instead, Porsche concentrated on making it lighter and sharper. Extensive weight-saving measures have shaved around 31.6kg from the donor car, despite the GT2 RS Weissach already being heavily optimised for weight. Carbonfibre features prominently, while other components have been reworked as part of the transformation. The interior has also received the Sonderwunsch treatment, with lightweight materials and bespoke details continuing the motorsport-inspired theme. The cabin is still recognisably a 911, but the extensive customisation gives it the kind of exclusivity you’d expect from a one-off Porsche.
Interestingly, Porsche’s decision to create this car also explains something that had enthusiasts scratching their heads. In May 2025, the company registered the Flachbau and Flachbau RS names with the European Patent Office, sparking speculation about a new slantnose model. The mystery has now been solved: those registrations were connected to this one-off project rather than signalling a new production model. And that makes the Flachbau RS even more special. It’s a one-off, road-legal Porsche that takes one of the most extreme 911s ever built. The original Flachbau was born from a desire to bring racing-car drama to the road. More than 40 years later, this one does exactly the same thing, just with considerably more performance.
