BMW trademarked the name 555i last year and it is expected that it will replace the 550i in the lineup. The 555i is going to be powered by a 4.4L twin-turbocharged V8 that puts out 400 horsepower and 450 lb-ft of torque. This is the same engine in the 2009 BMW X6 xDrive50i.
It is expected that this change will happen when the all-new 5-Series launches in 2009 as a 2010 model.
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