Porsche Flachbau RS resurrects slantnose 911

Ever wondered what Sonderwunsch and Manthey might be able to do with a GT2 RS? Here's your answer

By Matt Bird / Saturday, 15 August 2026 / Loading comments

Almost eight years ago now, Porsche showed the world a new 935, built from a 991 GT2 RS and evoking one of the most famous 911-derived race cars of all time. Now the concept has been taken one step further, both in terms of performance and nostalgia: this is the Porsche Flachbau RS.

Once more built from the 700hp GT2 RS and representing one customer’s vision of a modernised Moby Dick, the Flachbau brings back the slantnose 911 look not seen since the '80s. Back then it allowed 911 Turbo customers to get a look like the 935, and almost a thousand people took Sonderwunsch up on the offer 40 years ago. Now, with Special Wishes churning out one offs like they’re going out of busin… with Sonderwunsch demand increasing of late - think cars like the Carrera GT restoration, the GT3 956 homage and the Classic Club Coupe - there was only one place to turn for a customer who wanted “even greater performance and a Flachbau look, combined with a rear wing à la 911 GT3 R rennsport, please.”

Or, as it turned out, in more than one place; Sonderwunsch collaborating with Manthey, Porsche Motorsport and Style Porsche over three years to create the Flachbau. Enough time was invested, in fact, for the designer Grant Larson to have retired. As well as the flatter front wings that any Flachbau Porsche must have, he has pointed to staggered headlights as a “key feature”. See despite the vibe, this is a fully road legal Porsche just like the family Macan, and as such needs lights - tricky with the slantnose. So the LEDs for low beam and high beam are just four centimetres thick, the DRLs less than an inch. So probably not coming to the configurator anytime soon.

What’s also interesting given the look (and the Flachbau RS moniker) is the fact that this 911 is mechanically unchanged. Sure, that still means a 700hp flat six and seven-speed PDK, if a little unexpected for a factory-built one-off. Instead, the RS vibes come from a weight loss programme, taking more than 30 kilos from a GT2 RS with the removal of the infotainment, a lot of sound deadening and some floor coverings. Even surplus wires have now been taken. Which doesn’t sound great for covering miles in roadgoing 911, but then this isn’t likely to see the A14 anytime soon.

And despite so much having been taken out, there’s definitely new kit of interest as well. Note the ‘Flachbau RS’ embroidery, gold Sonderwunsch badge and ‘emergency box’ with the warning triangle and towing eyes in. Because the normal mounting points have been removed. Which sounds a lot like making work for the sake of it, but such is the way.

And while it might be easy to dismiss the Flachbau as a Grand Prix White elephant, there’s some proper substance behind the retro style as well. The front splitter works in conjunction with some Manthey magic underneath to smooth out airflow towards the diffuser, with aerodiscs - wouldn’t be a racy 911 without those - also reducing drag. It’s the spoiler that’s the real star attraction, though, design aping that seen on the latest GT3 R rennsport but towering five centimetres taller on its S-shaped mounts.

The new patented design has high downforce and low downforce settings, both offering up bigger numbers than a plain old Manthey Kitted GT2 RS; at the 211mph top speed in maximum attack, 554kg is claimed. Extensive testing, with three mules made, hundred of miles on the ‘ring, airfield runs, Weissach sessions, CFD analysis and rig time, is said to have put the equivalent of 90,000 miles average use through the spoiler. Racer Lars Kern reckons the Flachbau RS “extremely stable and precise even at very high speeds”, should the lucky customer be brave enough…

“Converting the car to a slantnose model proved to be very challenging, even though we left the drive unchanged, in agreement with the customer,” explains Alexander Fabig, Porsche’s VP of Product Offering Individualisation. “Our aim was to reinterpret the iconic look of the 935 without compromising on safety, technology or road legality.” It’s likely to cause a stir on the lawn at Pebble Beach, that’s for sure; nothing gets Porsche people excited quite like one-off unobtanium. Don’t expect this to be the last of its kind, either, because there must be money to be made. Bring on that Cayenne Transsyberia tribute…