Following in the inspiration & design footsteps of a rather special Porsche 917 that first took to the road a half century ago now, this extreme one-off developed from the marque’s successful WEC and IMSA championship winning machine made a stunning road debut near the Circuit de la Sarthe with its race born sibling, just before 2025’s 24 Hours of Le Mans race. Paying homage to that 917’s trailblazingly adventurous drive, the 963 RSP was conceived by Porsche Penske Motorsport and Porsche Cars North America, together with motorsport legend Roger Penske whose initials are reflected in the car’s name itself after he was nominated as its ideal owner.


It was in April 1975 that 917 #030 undertook its extraordinary pubic road journey from the Zuffenhausen factory right to Paris, driven of course by its enigmatic owner Gregorio Rossi di Montelera himself. “Count Rossi” had insisted that it incorporate the bare minimum of alterations for road use & remain as close to the race car as possible; until this very day, it resides in France and still enjoys occasional spirited road use just as the Count intended.


The 963 itself was initially the brainchild of Porsche Cars North America President and CEO Timo Resch who had expected to face resistance at first, yet every step of its planning and execution was met with the factory’s approval. He remarked, “This really started out as a “what if?” – a passion project by a small team of enthusiasts at Penske and at Porsche who together imagined a version of the 963 that really resembled as closely as possible the spirit and appearance of the Count Rossi 917. The 917 from the story was every inch a race car – albeit one driven on the road – and we took the same approach with the 963 RSP. It uses beautiful materials of the best quality available, but is still every bit a race car underneath.”


Being based on a rather more complex purpose built modern race car, the 963 RSP does feature more extensive changes than its illustrious forebear. It received a specifically configured mechanical and electronic setup for its Le Mans street debut, including more compliant dampers, a raised ride height and reprogramming of its control unit to operate the headlights and taillights in a more road suitable manner. Along with bodywork adapted to cover the wheel arches, Michelin wet weather tyres and the fitment of a horn, these modifications resulted in the French authorities granting it special permission to drive on the road, complete with license plates and the Automobile Club de l’Ouest (ACO)’s enthusiastic support.


Taking the 963 RSP’s controls for its first road miles, Porsche factory driver Timo Bernhard who has extensive competition experience with its race sibling said, “That was an experience that will stay with me for a lifetime. Driving down a public road with a 917 beside me – it felt unreal. The car behaved perfectly – it felt a little friendlier and more forgiving than the normal 963 – and felt super special and a lot more comfortable, especially as I was not needing all my safety gear.”


Roger Penske himself added, “We have enjoyed a terrific relationship with Porsche dating back to 1972. The Porsche 917/30, in particular, was one of the greatest eras in Team Penske history with numerous wins and championships, along with the closed-course speed record set by Mark Donohue in 1975. With such a remarkable partnership continuing to this day, we felt it was time to create the most exciting car we could imagine. Just like the 917, I wanted this car to be authentic to its origin and have as few changes to it as possible. When we got into the project, the differences in the two generations of race cars provided a great challenge. What emerged is a car that has lost none of its edge and is exciting whether on the track or on the road.”


Once the concept was established, Zuffenhausen’s Sonderwunsch team began making it a reality in close collaboration with their Sonderwunsch colleagues at Atlanta’s dedicated Porsche Classic facility opened in 2023. Inspired by Count Rossi’s 917 alterations made 50 years ago in 1975, Special Projects Director Grant Larson and his designers intended the 963 to reflect its original inspiration as closely as possible right down to the silver and black external color palette, with an interior that would be finished in tan leather and Alcantara. Its paint to sample color itself, Martini Silver with a triple-layer lacquer was verified from the Porsche Museum’s records to ensure authenticity.

Aligning it more closely with the 917’s form, further changes to the 963’s bodywork included uniquely louvered fender vents, in place of the race car’s fully open equivalents. Digitally rendered by Sonderwunsch and Porsche Penske Motorsport before being physically applied to the car, their aero optimized design still enables uncompromised wheel well ventilation. The race car’s regulated carbon fiber rear wing blanking plates could also be removed on the 963 RSP, further enhancing its aerodynamic effectiveness. An enamel Porsche badge sits proudly on its nose, as it does on the 917.

Further heritage details include a satin black finish used for minor components including the hinges & wing connectors, and a bespoke 3D-printed ‘963 RSP’ rear badge indicating the car’s unique status. Mounted on forged OZ racing wheels, the 18-inch rain tyres were even adorned with historic 1970s era Michelin logos.


Unlike the 963 race car’s ultra focused cabin, the 963 RSP’s interior also takes after the bespoke handcrafted example of the 917. Its one-piece air-conditioned carbon seat is re-trimmed in tan leather, with a fixed headrest affixed to the carbon fiber bulkhead and more comfortable soft central cushioning. Matching leather is also used to finish the multi-functional steering wheel, while the roof lining, pillars & footwell leg cushioning are retrimmed in light Alcantara. For those of you wondering if this 963 can even be used for coffee runs, the answer is yes provided you have the requisite computer equipment: there is even a detachable 3D-printed cup holder ideally formed to hold a Porsche travel mug.


A new trimmed panel beside the driver houses the 963 RSP’s Peltor headset and steering wheel when stowed, along with a platform for the aformentioned laptop that starts the car & governs its operations; plus Roger Penske’s bespoke carbon fiber helmet with matching Martini Silver accents, naturally. More subtle finishing elements comprise the bespoke ventilation system end-plates that invoke the 917 flat-12 engine’s cooling fan, leather & Alcantara door trims, and a small alloy plaque denoting the car’s chassis number, location and date of construction.


Power for the 963 comes from the Type 9RD 4.6 liter twin-turbocharged V8 engine producing an approximate maximum of 680 hp, originated from the 3.4 liter MR6 V8 engineered completely in-house to propel Porsche’s RS Spyder race program to clinch all 2006-2008 LMP2 class titles with Penske in the American Le Mans Series. This truly race bred motor was adapted into 4.6 liter Type M18.00 form for 2013’s limited production 918 Spyder super sports road car, optimizing its low center of gravity thanks to the flat crankshaft & short stroke that enabled a very low mounting point. Although naturally aspirated in that application, the 963 has now paired it with two Van der Lee turbochargers boosting at moderate pressures on the engine’s hot side for ideal throttle response. The 9RD engine also has around 80% parts commonality with the 918 Spyder’s M18.00, since it was already engineered to work with a hybrid system.

Here the electric boost system combines a standardized Bosch motor generator unit (MGU), electronics and software with a high-voltage battery by Williams Advanced Engineering. Mounted in a bell housing between the V8 engine and Xtrac 7-speed sequential gearbox with which it is directly integrated, the MGU boosts power output during acceleration while recuperating energy from the rear axle under braking. The entire powertrain retains its standard race tune, although the MGU has been remapped to smoothen its delivery for road use.
In line with this, the 963 RSP’s ride height is also raised to the maximum available setting, while its Multimatic DSSV adjustable dampers have been configured in their softest setting for more ride compliance. With all said & done, this incredible machine is capable of being driven on the road under special circumstances according to local requirements while wearing French ‘W’ or manufacturer license plates. However the 963 RSP will not be Porsche’s next homologated limited production model as expected, rather it will remain a very special one-off just like its iconic 917 predecessor.

Having been displayed during this year’s 24 Hours of Le Mans race at the Circuit de la Sarthe much to many attendees’ delight, the 963 RSP now returns to the Porsche Museum in Stuttgart. Its next appearance together with the 917 that inspired it will be at the Goodwood Festival of Speed in July.