920 horsepower just rolled through Los Angeles in a Porsche shell wearing a carbon-fiber exoskeleton, and Jay Leno called it “very American.” It was engineered in Northamptonshire, England. That tension tells you everything worth knowing about the RML GT Hypercar P39.
RML Group — a British motorsport firm founded in 1984 by ex-racing driver Ray Mallock — has spent four decades running factory programs for Vauxhall and Nissan at Le Mans and in BTCC. The P39 is their 39th road-car project: a 992.1 Porsche 911 Turbo S stripped, scanned, and rebuilt into a street-legal, Le Mans GT1-inspired hypercar. Only 39 customer cars will exist, and one of them just turned heads on an LA street.
What RML Actually Did to This Porsche
Every panel, every aero surface, and every suspension component is bespoke — this is not a body kit.
RML replaced the 911’s aluminum-and-steel body with a carbon-fiber skin that widens the track by 100mm and extends the wheelbase by 25mm. The rear glass is gone — a large carbon roof scoop feeds cool air directly to the engine, a design choice that reads less “tuner shop” and more “McLaren Senna.” The active aero package includes a dual-element rear wing with driver-activated DRS — think F1: it flattens the wing on straights to cut drag, then snaps back for cornering grip. At 150mph, the car generates roughly 662kg of downforce. That’s not a number you feel; it’s a number that corners for you.
- Base car: Porsche 992.1 911 Turbo S — stock 640hp, 0–60 in 2.6 seconds
- After RML and Litchfield Motors: 920hp larger turbos upgraded intercoolers, and an Inconel exhaust
- Driving modes: Wet (~600hp, softened throttle), Normal/Tour (750hp, hushed exhaust), Sport+ (full 920hp, open exhaust valves — this is what Leno heard)
- Production: 39 customer cars plus car zero; first ten are “40th Anniversary” editions
- Cost: From approximately £520,000 for the conversion alone, before the donor car or personalization
The Sound Jay Leno Couldn’t Stop Talking About
In Sport+ mode, with exhaust valves open and peak torque arriving at 4,500rpm, the P39 announces itself in a way that leaves little room for polite conversation.
The car Leno drove is No. 6, a 40th Anniversary edition finished in orange chosen by IndyCar driver Graham Rahal — son of 1986 Indianapolis 500 winner Bobby Rahal. Graham Rahal Performance in Zionsville, Indiana serves as the official US importer, which is why this particular example is the first P39 on American roads rather than sitting in a Northamptonshire car park.
Engage Sport+ and the Inconel exhaust valves open wide. The transmission stops being polite. Leno said the car “makes all the right noises” — then joked he was moving too fast to be entirely certain. His “very American” verdict lands as a compliment to the car’s sheer theatricality: loud, dramatic, and unapologetically over-engineered. The irony holds: British craftsmanship, German platform, orange muscle-car energy.
RML developed the entire car digitally — no clay models — moving from concept in roughly August 2024 to a running prototype by May 2025. The company targets a Nürburgring lap of around 6:45, which would reportedly beat the factory Porsche GT3 RS, though that remains an internal aim rather than a confirmed result. Inside, Porsche’s climate control and infotainment stay stock; Recaro seats replace the originals. The duality is the whole point — hypercar downforce paired with ergonomics civilized enough to drive to dinner.
Thirty-nine people on earth get to order one. For everyone else, there is always the sound Leno heard echoing through Los Angeles — the kind that stays with you longer than the car does.
