► Porsche-built one-off slantnose special
► Based on 911 GT2 RS with Manthey upgrades
► Finally solves ‘new Flachbau’ mystery

There are, no doubt, stacks of custom, low volume, limited issue, reimagined and remastered Porsches at the 2026 Monterey Car Week. But only the owner of this car has a one-of-one Sonderwunsch slantnose special, built by Porsche itself. The automotive equivalent of a mic drop, if ever there was one.

While visually it’s a bit… challenged from some angles, this unique Flachbau RS is the result of almost three years of extensive development work that (thankfully) demonstrates it’s much more than just a pretty face.

That flatnose front end is a tribute to the 930 Turbo Flachbau road cars, which themselves were tributes to the 935/78 Moby Dick Le Mans car (middle above), and most closely resembles the limited-run track-only 935 tribute of 2018 (left above). But this is a bespoke development and entirely road legal.

What’s more, it’s lighter and more aerodynamically impressive than the 991.2-generation 911 GT2 RS it’s based on, thanks in no small part to enhancements developed by Porsche’s now notorious skunkworks racing outfit, Manthey Racing.

What’s the spec and who was involved?

While there are no powertrain upgrades over the 691bhp GT2 RS donor car, a ‘like new’ 2018 Weissach Package example originally finished in yellow, much else has been significantly overhauled. For instance, keeping in mind that the GT2 RS Weissach was already highly optimised from a weight perspective, the Flachbau is some 31.6kg lighter.

The visual changes were penned by Grant Larson for the Porsche Sonderwunsch (that’s ‘special requests’) department, which created the car in partnership with Porsche Style and others we’ll get to in a moment. Larson also did the modern 935 of 2018, also based on the GT2 RS, although here most of the modifications are focused on the front.

In addition to the revised nose and flattened front wings, a special set of stacked LED lights replace the pop-up headlights of previous road-going slantnose Porsches from the 1980s. The aerodynamic changes at this end are balanced out by a taller – but still adjustable – rear wing that uses S-shaped mounts inspired by the 992-generation 911 GT3 R rennsport.

Much of the aerodynamic trickery is either more subtle or hidden on the underside of the car, though, and comes courtesy of Manthey. Now a majority-owned subsidiary of Porsche AG, Manthey’s official involvement with Porsche’s most extreme road cars began with the 991.2 911 GT2 RS, which claimed the official road-legal lap record on the Nürburgring Nordschleife in 2021.

In fact, the 911 GT2 RS MR is still Manthey’s fastest car on the ‘ring, with subsequent models based on naturally aspirated GT3 and GT4 variants unable to match its stunning 6:43.3sec time over the longer modern full lap. Manthey’s physical enhancements to the new Flachbau RS include the front flaps and splitter, full underbody structure and rear diffuser, plus the trademark aerodiscs on the rear wheels.

The resulting car has undergone simulated crash testing, virtual and physical aerodynamics testing, and a full development programme involving engineers from Porsche’s Weissach test facility, Porsche Motorsport and Manthey.

But it’s just a show car, right?

Wrong. Three test vehicles were created to ensure the final version met validation standards, and the programme included 50 laps of the Nürburgring – where it prompted all sorts of new slantnose speculation – and loading the rear wing with the equivalent of 150,000km (93,000 miles) of real-world use.

Important, presumably, given in its high downforce setting that rear wing generates 554kg of downforce over the rear axle – while still managing a top speed of 211mph.

It was driven at the ‘ring by Lars Kern, the driver responsible for many of Manthey’s lap records, including that 6:43.3. He praised the new car’s ‘aerodynamic concept’, saying: ‘The Flachbau RS remains extremely stable and precise even at very high speeds. This is exactly the kind of feedback needed in order to validate such a radically altered body design.’

Anything else we should know?

The exterior is painted Grand Prix White, sampled from a historic 911 in the firm’s own heritage collection. The contrast elements – finished in a mixture of black and raw carbonfibre – are intended to echo the Martini livery of the 935/78 Moby Dick.

The changes at the front meant redesigning the fuel filler mechanism, and the new, lower-slung front wings are vented to relieve aerodynamic pressure.

On the inside some of the donor car’s black leather and red Alcantara remains, but this is also where plenty of obvious sacrifices were made to save weight. The rear of the cabin has been stripped of trimming, the infotainment and hi-fi system has been binned – bit of a curious decision when creating a road car, but each to their own – and the new wiring harness left exposed. There’s not much sound-deadening left, either.

Exposed painted surfaced – also Grand Prix White – and carbonfibre complete the race-car look. The special nature of this vehicle is further emphasised by the Flachbau RS letting over a Nürburgring outline on the headrests, plus a Sonderwunsch badge and a plaque inscribed ‘Factory One-Off 2025 | Flachbau RS’ on the dashboard.

The unveiling of this car in Monterey also solves a minor moder mystery – explaining not only the Nürburgring prototypes but also why Porsche registered the model designations Flachbau and Flachbau RS with the European Patent Office in May 2025. That’s a hell of a lot of effort for a one-off.

Mic. Drop.