Porsche Flachbau RS Is a New Slantnose 935 Moby Dick

Porsche slantnose devotees may recall that, in May 2025, the company filed registrations for ‘Flachbau’ and ‘Flachbau RS’ with the European Patent Office. This extraordinary bespoke creation reveals the reason: meet the – yes, really – Flachbau RS.

Based on a customer-owned 991.2 911 GT2 RS, an already fearsome car, it has been reworked by Porsche’s internal special-projects division, Sonderwunsch, to resemble ‘Moby Dick’. That means not the whale, but Porsche’s famously formidable and ‘monstrous’ historic racing machine.

“Our aim was to reinterpret the iconic look of the 935 without compromising on safety, technology or road legality,” said Porsche’s VP of individualisation Alexander Fabig. Correct: this car is approved for use on public roads.

Porsche Flachbau RS reinterprets the 935 Moby Dick

Conveniently, the one-off’s styling was created by the man responsible for the 2018 reimagining of the 935: Grant Larson. Porsche says Larson has since retired, but he described his latest work as follows: “The new Flachbau RS is a modern, fitting reinterpretation of the iconic 935 Moby Dick design.”

Converting the GT2 RS into a slantnose was evidently not a quick job. It gains lower, redesigned front wings, extra louvres, a fresh front bumper and an especially striking LED lighting arrangement. The lamps are split across three levels for main beam, dipped beam and daytime running lights.

Porsche’s close associate Manthey also contributed to the project. The result includes a new front splitter, a rear diffuser, improved aerodynamics over the standard car and an enormous rear wing. That wing is manually adjustable between three settings according to the required level of downforce – and yes, this Porsche is very serious indeed.

With its wing in the ‘high’ setting, it generates 554kg of downforce. It is also 31.6kg lighter than the donor GT2 RS, which itself has the lightweight Weissach Pack, making this an exceptionally light machine.

Unchanged GT2 RS power and an uncompromising cabin

Porsche left the GT2 RS powertrain alone – understandably so. Its 3.8-litre twin-turbo flat-six already produces nearly 700bhp and 553lb ft, delivers 0-62mph in 2.8s and reaches 211mph. One does not simply… add power to a GT2 RS.

The body wears a bespoke ‘Grand Prix White’ finish, set off by contrasting black details, stripes and aerodisc wheels. Inside, the cabin has been stripped out to an extreme degree. At the owner’s request, Porsche removed the PCM system, audio equipment, sound insulation and even the floor coverings.

Consequently, the interior consists largely of painted metal and exposed carbon fibre. The wiring loom is visible too, and, in typically meticulous Porsche fashion, was lightened by deleting “individual wires that were no longer needed”. There is lightweight gearshift-gaiter material, and then there is this.

Look closely and there is ‘Flachbau RS’ embroidery, carbon-fibre bucket seats and a Nürburgring inscription. The final detail is more than decoration: Porsche completed 50 laps of the Nordschleife in a validation prototype, one of three produced. Porsche test driver Lars Kern said that around the ‘Ring it remained “extremely stable and precise even at very high speeds”. Job done, then.