BMW's top-selling 3 Series line receives an important re-engineering for 2006. The sedan and wagon body style were the first to be influenced by the new 2006 3 Series style that also includes more powerful engines. Not only does the 2006 model year represent the return of the M5, the 6 Series receives its first-ever influence from the BMW M division. On both the BMW M5 sedan and M6 coupe is propelled by a 500-horsepower V-10 engine. Performance is also being enhanced with the V-8 powered version of the conventional BMW 6 Series. A new 650CI features a 4.4-liter V-8 engine generates 360 horsepower (a 35 horsepower improvement over its predecessor). All-wheel drive is now available on the 5 Series line-up that also marks the return of a wagon body style in the United States for 2006. The sport roadster Z4 line is expanded with two new models for 2006. First is a fixed-roof BMW Z4 and the second is a performance-oriented Z4 M. The base BMW X3 2.5i model is dropped for 2006 leaving the more potent 3.0i the only choice.