The BMW 650i Coupe and 650i Convertible are nearly identical in temperament and equipment. A slight change in nomenclature for 2006 (both were previously called the 645Ci) reflects an increase in engine size. The V8 has grown to 4.8 liters, with an increase of 35 horsepower and 30 pound-feet of torque, peaking at 360 in both cases. This engine is packed with the latest in materials and control technology. A six-speed manual transmission is standard, but either a six-speed automatic with the Steptronic manual shift feature or a six-speed sequential manual gearbox (no clutch pedal) is available as a no-cost option.For 2006, the BMW 650 gets more power.