Mark Rankin owns a unique 2003 BMW E46 M3. Although the car came from the factory with a 3.2 L S54B32 inline-six, it’s now powered by a RB25 inline-six from a Nissan R33 Skyline. The RB25 produces around 600 horsepower thanks to forged internals, a Precision 6266 turbocharger, and water methanol injection. Behind the motor sits a BMW M3 Getrag 420 six-speed manual transmission with a PMC Motorsport adapter kit which sends power to a M3 rear end.
Source: Mark Rankin and PMC Motorsport FB page