Porsche Sonderwunsch Unveils One-Off GT2 RS 'Flachbau RS' Homage to 1970s Moby Dick

Key points

• The Flachbau RS is a one-off Sonderwunsch creation based on a 991.2 911 GT2 RS, developed over three years for a specific customer.
• The design reinterprets the 1978 935/78 'Moby Dick' with new front fenders, slatted louvres, and a cascading LED light system replacing the standard round headlights.
• Aerodynamic upgrades include a new rear wing inspired by the 911 GT3 R Rennsport, Manthey front splitters, and carbon-fiber aero discs, generating up to 1,221 pounds of rear-axle downforce.
• Weight was reduced by 31.6 kg (approx. 70 lbs) through the removal of the audio system, PCM, sound insulation, and floor coverings, resulting in a bare-metal interior aesthetic.
• The powertrain remains unchanged from the base GT2 RS, featuring a 3.8-liter twin-turbo flat-six producing 700 horsepower and 553 pound-feet of torque.
• The car completed over 1,000 km of endurance testing at the Nürburgring, including 50 performance laps with sub-seven-minute times, ensuring stability and road legality.

Background

Porsche’s Sonderwunsch program has previously produced notable one-offs, including the 993 Speedster and the Buzz Lightyear GT3 RS. The Flachbau RS follows the lineage of the 1980s road-going Flachbau models and the 2018 935 reinterpretation, which was also designed by Grant Larson. This latest project represents a modern, performance-focused evolution of the historic slant-nose silhouette, distinct from earlier decorative special editions.

How outlets are covering it

Motor1 emphasizes the car’s visual departure from standard 911s and its status as a top-tier Sonderwunsch creation, highlighting the unique lighting and paint scheme. Porsche’s official release focuses on the engineering rigor, detailing the 1,000 km Nürburgring testing and the balance between heritage aesthetics and modern performance. Top Gear notes the involvement of designer Grant Larson and the specific patent registrations for the 'Flachbau' name, while also pointing out the extreme weight reduction measures, including the removal of individual wiring harnesses. Car and Driver provided visual documentation but limited textual analysis, focusing on the car’s presence at The Quail.

Why it matters

The Flachbau RS demonstrates the extreme limits of Porsche’s customization capabilities, showing how a production track car can be fundamentally restructured for aerodynamic and weight benefits while maintaining road legality. It highlights the enduring cultural impact of the 1970s Moby Dick design and the premium value of bespoke, one-off engineering in the luxury automotive sector.

What to watch

The Flachbau RS is scheduled to be displayed at The Quail, A Motorsports Gathering, in Monterey. Porsche has indicated that while they may evaluate similar requests, the exact one-off nature of this build means a duplicate will likely never be produced for another customer.