Both engines incorporate direct fuel injection and turbocharging. The xDrive35i uses a new 3.0-liter inline-six-cylinder with one turbocharger, while the xDrive50i uses a 4.4-liter V-8 with two. Power ratings are unchanged on the new six-cylinder, but BMW says it is more efficient. BMW says both engines promise minimal turbo lag and a flat torque curve that begins under 2,000 rpm.

300-horsepower, 3.0-liter six-cylinder with 300 pounds-feet of torque (xDrive35i)
400-hp, 4.4-liter eight-cylinder with 450 pounds-feet of torque (xDrive50i)
New eight-speed automatic transmission
xDrive's Dynamic Performance Control doles out power from front to rear and side to side, at least among the rear wheels
Differential electronically varies power proactively from a full 50/50 lock to as much as 100 percent going to either wheel to enhance performance and safety
Adaptive Drive system electronically alters suspension's stiffness between sport- and comfort-oriented settings to suit different driving conditions