The 528i is furnished with a standard 3.0-liter, I6, 240-drive motor that attains 22-mpg in the burb and 32-mpg on the parkway. The 550i xDrive is furnished with a standard 4.4-liter, V8, 400-drive, turbo motor that attains 16-mpg in the burb and 24-mpg on the parkway. A 8-speed mechanical transmission with overdrive is standard on both trims. 2011 BMW 5 Series