The N54 I-6 (twin turbo from the 335i etc.) has won back to back International Engine of the Year awards.
BMW also won awards for the 1.4-1.8l class with the BMW-PSA 1.6l turbo utilized in the MINI line up, in the 3-4l. category for the V8 in the ///M3, in the above 4l category for the V10 in the ///M5/6 and best new engine of the year for the 2.0l diesel in the 123d.
I guess you can say BMW makes great engines, something we enthusiasts have known for a long time!

BMW 3-LITRE TWIN TURBO (135, 335, X6)
“Outstanding in power output, low-end torque, refinement and fuel economy. Top marks to BMW”
Arturo de Andrés, Automóvil

By completing back to back wins at the International Engine of the Year Awards 2008, BMW’s 3-litre Twin Turbo petrol unit has matched the feat achieved by its V10 in 2005 and 2006, and secures back-to-back overall wins at the event. The result also confirms turbocharging as the power generator of choice, as the engine’s triumph here makes it one of seven categories scooped by turbo engines.

With an impressive 380 points – finishing nearly 100 points ahead of the Volkswagen’s TSI – the 2,979cc unit proved to be a hit with jury members the world over. Many were wowed by its sheer performance, or recognised the significance of the debut of BMW’s high-precision direct-injection system, which helps to maximise performance and fuel economy by precisely dosing the air-fuel mix. Adoption of the system also enables a higher compression ratio (10.2:1) for better fuel economy as well as a more efficient method of combustion chamber cooling.

John Carey from Wheels magazine said the unit is “proof that BMW pushes the boundaries of engine technology more than any other manufacturer”. Auto’s Lorenzo Facchinetti thinks it is a “gorgeous engine that has the ability to make a 1-Series or 3-Series feel like an old M3, with much more fluidity and fuel efficiency”. And Schalk Pienaar from Wiel commented that it shows “good use of available technology to lower fuel consumption and provides smooth and strong power delivery”.

The two small turbochargers – rather than one larger unit – each supply three cylinders to ensure a more rapid response to throttle position throughout the rev range, and also eliminate lag.

The last words on the powerplant should go to a clearly overwhelmed Hormazd Sorabjee, editor and publisher of Autocar India: “There is something simply magical about BMW’s in-line six. It has a creamy smoothness that makes velvet feel like sandpaper.”

BMW Release:

BMW STRAIGHT SIX-CYLINDER ENGINE WITH TWIN TURBO DEFENDS ITS TITLE OF “INTERNATIONAL ENGINE OF THE YEAR ”
05/07/2008

Munich / Stuttgart. With six awards for five engines gained at this year ‘s “International Engine of the Year Awards “, BMW has successfully defended its position as the world ‘s leading manufacturer of efficient high-performance power units. For the second time in succession, the 3-litre straight six engine with Twin Turbo and High Precision Injection has won the overall ranking in this most significant international engine competition. The 225 kW/306 bhp engine employed in the BMW 3 Series, the BMW 1 Series Coupe and Convertible, as well as in the new BMW X6, also has repeated last year ‘s victory in the 2.5 to 3-litre engine category.
Only one engine had previously ever succeeded in repeating overall victory at the “International Engine of the Year Awards “: the 5-litre V10 high-revving power unit employed in the models BMW M5, BMW M5 Touring, BMW M6 Coupe and BMW M6 Convertible received first prize in 2005 and 2006. This year the 373 kW/507 bhp high-end power unit won the Above 4-litre category. The BMW M GmbH was successful in positioning a further winner: the 309 kW/420 bhp V8 engine boasted by the new BMW M3 won the category for engines in the 3 to 4 litre category. Furthermore, the 2-litre four-cylinder diesel with Variable Twin Turbo employed in the BMW 123d received the award for “Best New Engine ” of the 2008. And the 1.6-litre four cylinder with Twin Scroll Turbocharger and direct petrol injection employed in the MINI Cooper S managed to repeat last year ‘s win in the engine class 1.4 to 1.8 litres.

For the first time in the history of the competition, the title “Best New Engine of the Year ” has been awarded to a diesel engine. The 150 kW/204 bhp four-cylinder diesel with Variable Twin Turbo has earned this award due to a unique relation between performance and efficiency. As the world ‘s first full-aluminium diesel power unit it delivers a specific output of more than 100 bhp per litre of displacement. At the same time it facilitates in the BMW 123d an average fuel consumption of 5.2 litres per 100 km in an EU test cycle and a CO2 emission level of 138 grams per km. This renders it a fine example of the consistent realisation of the BMW EfficientDynamics development strategy.

With its current win of six trophies, the BMW Group continues to impressively dominate the engine competition which has been held now for ten years. The repeated success of the straight six engine with Twin Turbo is already the sixth overall victory for the company since the foundation of the “International Engine of the Year Awards ” in 1999. The bandwidth of the BMW Group ‘s currently successful engines is also remarkable. They range from the 128 kW/175 bhp four cylinder of the MINI Cooper S to the two high-revving power units produced by the BMW M GmbH.

The “International Engine of the Year Award ” has been presented since 1999 by an international jury consisting of highly prominent car journalists. This year the team of experts comprises 65 top journalists from 32 nations which include the USA, Japan, China, Russia, India, Germany, France, New Zealand, Korea and South Africa and, this year, Romania and Poland. Prizes are awarded for eleven categories as well to the winner of the overall rating. The award ceremony will be held on 7th May during the “Engine Expo 2008 ” in Stuttgart.