Rare BMW E39 M5 with Volkswagen W10 Engine Heads to Auction
A truly exceptional 2000 BMW E39 M5, a vehicle concealing a prototype Volkswagen W10 engine, is poised to go under the hammer. This unique automobile, originally commissioned by then-Volkswagen chairman Ferdinand Piëch as a clandestine engineering project, showcases a fascinating cross-brand collaboration. With only three such W10 engines ever produced, and this M5 being the sole road-going example, it represents a significant piece of automotive history. The car's impending auction offers a rare opportunity for collectors to acquire a vehicle that defies conventional automotive classifications, blending the iconic design of the E39 M5 with the experimental heart of a Volkswagen powerhouse.
This extraordinary vehicle is scheduled for auction by Broad Arrow Auctions at the Zoute Concours in Knokke-Heist, Belgium, on October 9, 2026. Experts anticipate bids between €250,000 and €350,000, roughly $285,000 to $400,000. The project's inception dates back to 1999 when Ferdinand Piëch, known for his engineering-first philosophy, instructed his team to integrate a W10 engine into a high-performance sedan, a segment where Volkswagen and Audi lacked a direct competitor to BMW's M5.
Instead of developing a new test chassis, Volkswagen engineers ingeniously transplanted the experimental W10 engine into a 2000 E39 M5, replacing its standard S62 V8. The M5, a chassis dated March 2, 1999, retained its original six-speed manual transmission. Outwardly, the car appears to be a standard Carbon Black Metallic M5 with black leather interior, chassis number WBSDE91040GJ16436. However, under the hood lies its secret – a naturally aspirated, all-aluminum 5.0-liter W10 engine, generating an impressive 473 horsepower and 437 lb-ft of torque. This output surpasses the original S62 V8 by 79 hp and 68 lb-ft, offering a preview of the power that would eventually define the quad-turbo W16 engine in the Bugatti Veyron.
The conversion involved deactivating the traction and stability control, as well as the anti-lock brakes, with an independent ECU managing the engine. The factory instrument cluster was replaced with an aftermarket Stack racing dash, which unfortunately means the vehicle's precise mileage is unknown. The current owner, who acquired the M5 approximately a decade ago through engineering connections, has road-registered it in Slovakia and regularly drives it. However, due to the extensive modifications, obtaining a certificate of conformity remains a challenge for the future owner.
Sabine Willeke, who led the engineering team on this project, confirmed that only three W10 engines were ever constructed. One engine is preserved in Germany, another is displayed alongside a stationary M5, and the third powers this specific vehicle, making it the sole active example in a road-legal car. Willeke also disclosed that this M5 served as Piëch's personal transport during its discreet development, a project conducted outside Volkswagen's official research and development channels at an estimated cost of nearly €2 million ($2.3 million). Despite the significant investment and groundbreaking engineering, the W10 concept never progressed beyond this prototype stage, and Volkswagen ultimately abandoned the idea.
This auction presents a compelling dilemma for collectors: whether the car's extraordinary provenance and unique engineering outweigh the loss of its factory originality. The successful bidder will also assume the responsibility of navigating the registration and conformity processes, making this a prime target for museums or private collectors with access to specialized automotive experts. The outcome of this sale will be closely watched, as a robust result could signal a burgeoning market for one-off prototypes and re-engineered vehicles, potentially elevating them to a new category of highly sought-after collectibles.