"What if we homologate it?": The story of the race car that can travel on roads and highways

Porsche had a strong showing at the 2025 24 Hours of Le Mans , finishing second overall and challenging Ferrari's current dominance, which ultimately resulted in the victory. But the race saw something unfold that had only happened half a century ago.

The 963 RSP was on display at one of the German brand's exhibition spaces on the Sarthe circuit. This car was based on the prototype that competed in the world's toughest track race, creating a version suitable for traveling on roads and highways.

It's also a tribute to another Porsche race car that shone at the 24 Hours of Le Mans, which 50 years ago also underwent a homologation process to make a trip from Germany to Paris.

In this case, the 963 RSP traveled from Zuffenhausen, the German brand's headquarters in Stuttgart, to Le Mans, where it became the race's all-time winner, with a total of 19 victories since 1970.

This story also involves a count, who gave life to the original project, and the American Roger Penske , who with his racing team was in charge of making the modifications to the racing car.

In April 1975, a Porsche 917 , a long-standing fan favorite at the 24 Hours of Le Mans, was modified to travel from Zuffenhausen to Paris.

The then owner, Count Rossi, commissioned Porsche to make the minimal changes necessary to make the vehicle roadworthy. This sports car, originally a racing car, is still in perfect condition and can occasionally be seen driving around France .

That idea was the inspiration for today. “It all started with the question: What if...? ” explained Timo Resch, CEO of Porsche North America. That thought transformed “into a project driven by a small team of Penske and Porsche enthusiasts, who shared the vision of creating a version of the 963 as faithful as possible to the spirit and look of Count Rossi’s 917,” Resch added.

The basis of the project was the same Porsche 963 that finished on the second step of the podium at the 2025 24 Hours of Le Mans. The acronym RSP corresponds to the name of the team owner who carried out the transformation: Roger Searle Penske.

The chassis and body are practically identical to those of the competition prototype. Except that in this case, the carbon and Kevlar bodywork doesn't feature the decals that decorate these cars; instead, it's painted like any other car: the chosen color was Martini Silver , just like the 917 50 years ago.

Smaller body parts, such as the door hinges and wing joints, are finished in satin black. At the rear, a 3D-printed "963 RSP" inscription identifies this unique model.

Some of the visible changes that had to be made to allow road use were, for example, the fenders, which have custom-made vents that are usually open on the competition version.

Mounting points were also made for the license plate, and the logo is not a sticker but rather an enameled shield, like the production cars.

Ground clearance has been increased compared to the competition version, while the shock absorbers have been softened to improve ride comfort.

The vehicle's control units have been programmed to enable the cornering light function, and the headlights have been optimized for highway driving.

The 963 RSP doesn't have the same powertrain as the 963 World Endurance Championship, but it's also a hybrid. In this case, it's powered by a 4.6-liter twin-turbo V8 engine developing approximately 680 horsepower and originating from the RS Spyder racing program.

With this unit, Penske won every LMP2 title in the American Le Mans Series between 2006 and 2008. It was later used in the 918 Spyder, and was upgraded from 3.4 to 4.6 liters.

While the 918 Spyder used a naturally aspirated engine, the 963 is equipped with two turbochargers. In total, around 80% of the 963's engine components are identical to those of the 918 Spyder, which was already designed for hybrid powertrain use .

In turn, the electric motor (MGU), responsible for power delivery and recuperation during braking on the rear axle, works directly with the seven-speed sequential transmission. The MGU is located between the V8 and the gearbox. With this system, the car can be used in 100% electric mode.

The biggest visible change compared to the 963 race car is found in the RSP's interior. Here, too, inspiration was sought from the 917 converted into a road car in 1975, with a combination of light brown leather and Alcantara . While the race car offers very little comfort, the 963 RSP feels more accommodating.

The driver's seat is made from a single piece of carbon fiber and covered in leather, with a padded center section and a fixed headrest. As in the racing version, the seat is heated. The steering wheel, which controls most of the car's functions, is also covered in leather.

A striking detail is a removable 3D-printed cup holder . And to the right of the driver's seat is a special mount that accommodates headphones and the steering wheel when the vehicle is stationary. There's also room there for the laptop needed to operate the vehicle, as well as for the custom helmet, made especially for Roger Penske.

The 963 RSP was allowed to drive on local roads near Le Mans for its world premiere, thanks to modifications made in accordance with local regulations. It was also granted special authorization and the use of the French "W" license plate. However, due to its design and despite the modifications, it will still have some road restrictions. But it will remain a unique piece.