Countless BMW owners have been frustrated for some time with software-induced turbo lag on their N54 3.0-liter twin-turbo inline-6 engines. While early models were acclaimed for their immediate power delivery, it seems BMW felt it necessary to address "specific noise concerns" with the engine and made software changes in models built between June 2006 and March 2008. Those changes introduced turbo lag – the noticeable delay between the throttle and the time it takes for the turbocharger to spin and produce power. Enthusiasts were up in arms, but BMW refused to recognize their concerns (addressed on nearly every BMW message board, and by the BMW Car Club of America)... until now. According to a statement from the automaker, new software will be released in January 2009 that will restore the original turbocharger response. Of course, it comes with a warning that it may result in "slightly increased engine noise levels." As if an enthusiast cares... Thanks for the tip Michael!

[Source: BimmerFile]

BMW North America Statement:

"In an effort to address specific noise concerns, BMW updated the turbocharged engine software on 335i/xi and 535i/xi models built from June 2006 through March 2008. The updated software causes a small amount of increased "turbocharger lag" under certain circumstances and, while not substantial, the lag may be perceptible to the most sensitive BMW drivers. X6, 135i, and 3 Series/5 Series vehicles from March 2008 production onward are not affected. Release of the new software to restore the original turbocharger response is planned for January 2009, and it will be available for vehicles produced from September 2007 through March 2008 when they are brought to an authorized BMW center for a repair which requires a programming update. Clients with vehicles produced from June 2006 through September 2007 may request installation of the January 2009 software update. Clients who get this update should understand that there is a possibility of slightly increased engine noise levels under certain circumstances."