Lol, why not just go quad turbo and call it a day?
According to a post on the forums at GermanCarZone, BMW is currently working on a new version of its 3.0-liter six-cylinder diesel engine, which puts out 286 horsepower and 413 lb-ft of torque in its current, twin-turbocharged guise. To bump that power peak a bit higher, those crazy German engineers are rumored to be adding a third turbocharger that would boost horsepower to around 350.
This new tri-turbo diesel V6 would see its first application in a BMW X5 Performance Diesel. In a bid to maintain the oil-burners fuel efficiency, BMW would add hybrid componentry that includes stop/start and regenerative braking. These bits would earn the big SUV entrance into the automaker's Efficient Dynamics club.
In addition to the high-performance engine, the X5 Performance Diesel would reportedly get a unique body kit that includes subtle lips around the wheel arches along with revised air intakes and a front spoiler. It's too early to verify any of these rumors, but we'll be sure to keep our ears to the ground for more.