The BMW 650i nameplate belongs to the modern 6 Series family and first appeared in 2004, when BMW brought back the 6 Series as an exclusive grand touring coupe and convertible. The 650i sat at the top of the range in many markets and became the V8-powered flagship badge across the 6 Series Coupe, Convertible, and later Gran Coupe. It is associated with the second and third generations of the revived 6 Series, including the 2004-era E63/E64 cars and the later F12/F13/F06 family that expanded the line into coupe, convertible, and four-door form. The 6 Series itself eventually gave way to the 8 Series, ending the 650i chapter as a continuous BMW model line.
ALPINA B6 is a separate but closely related BMW-based nameplate built from the 6 Series. The first B6 appeared in 2006 on the E63/E64 6 Series base car, with ALPINA later updating it as the B6 S through 2010. After a gap, the name returned in the mid-2010s as the BMW ALPINA B6 Bi-Turbo, again based on the 6 Series Coupe, Convertible, and Gran Coupe. That later generation carried ALPINA’s traditional blend of long-distance comfort, discreet styling, and high-performance V8 character, positioning it as a more exclusive alternative to the standard BMW 650i. Because the B6 was discontinued and then revived, the overall nameplate history is not one continuous run.