Car of the Week: This Custom 1998 Porsche 911 Is One of a Kind. Now It’s up for Grabs.

As far as Porsche 911s go, this one is as rare as it gets. This 993-generation Porsche 911 Carrera S “Factory One-Off” Cabriolet was, as the name implies, the only factory-built example to come with a wide-body “Turbo Look” configuration. Completed in 1998 by the Porsche Exclusive Manufaktur division, and now with just 10,200 miles on the clock, it will be one of the stars of Broad Arrow’s Chattanooga Auction on October 12. The sales event is being held in conjunction with the 2024 Chattanooga Motorcar Festival in Tennessee, which will run from October 11 through 13.

“For the purist of air-cooled Porsche 911s, this is the ultimate prize,” says Ray Shaffer, respected Porsche specialist with Broad Arrow and Hagerty Marketplace, when describing the car to Robb Report. “It is a true one-of-one, and one of the rarest and most desirable creations ever to emerge from Porsche Exclusive.”

Back in the 1990s, if you were considered a Porsche VIP and had friends at the company in very high places, you could request to have a one-of-a-kind model built. That happened in 1997 with German collector Harald Otto Karrenberg, who asked for a unique 911 Cabriolet.

According to Shaffer, Karrenberg petitioned for an example from the then-new 993-generation (the last of the air-cooled 911s) in classic Guards Red. While the car he ordered would have a normally aspirated version of Porsche’s 3.6-liter flat-six engine, Karrenberg wanted the vehicle to have the wide-fendered styling reserved for the more potent Turbo coupe of the day. 

“It seems his initial request was declined. But with a little time and a lot of patience, the order was eventually given the green light,” says Shaffer, who adds that “once the car was rolled off the assembly line at Porsche’s Zuffenhausen plant, it was wheeled into the Porsche Exclusive workshop for customization.”

Here, in place off the 911 Turbo’s large, fixed “whale-tail” rear wing, the car was fitted with the more subtle Carrera S split-grille active rear spoiler. Other tailored accents include 18-inch hollow-spoke “twist” alloys from the Turbo, along with special Flamenco Red carpeting to contrast with the interior’s black Nappa leather seats.

Karrenberg reportedly treasured the car for over 17 years, meticulously maintaining it while putting only 16,200 kilometers (just over 10,000 miles) on the odometer. In 2018, the car was offered at the RM Sotheby’s Paris auction where it sold for €269,375 (approximately $317,900) to a well-known Porsche collector. 

Shaffer explains that under its new ownership, the car experienced an equally sheltered life, with fewer than 280 miles added to it during the last six years. Records show that, in 2022, the car went to Porsche’s Factory Restoration facility in Asperg, Germany, for an overhaul that resulted in it receiving the coveted Porsche Classic Technical Certificate. Work included major maintenance on the engine, convertible top, and suspension.

“I recently drove the car, and it really does feel as good as new. The smoothness of the ride, the response of the engine, and the way everything just works. This really is a time capsule,” says Shaffer.

Is it worth Broad Arrow’s $400,000-plus estimate? Shaffer points to the Porsche-built, one-off 911 Classic Club Coupe—based on a 996-generation 911—that’s also from 1998. That car sold at auction in Atlanta last year for a record $1.2 million. According to Shaffer, “Porsche enthusiasts, especially fans of the last air-cooled 993 models, will recognize this as a once-in-a-lifetime opportunity.” The singular Porsche is expected to fetch in excess of $400,000.

Click below for more photos of this 1998 Porsche 911 Carrera S “Factory One-Off” Cabriolet.