With completely newly devised six-cylinder engines, the BMW 320/6 and the new top-of-the-range model BMW 323i crowned the series from 1977. Both models convinced not only through performance alone (BMW 323i with electronically controlled engine management and transistor ignition, 105 kW/143 hp), but also through elasticity and running smoothness. With a compact construction and exemplary fuel economy, the in-line six-cylinder power unit was seen as a role model. During the late seventies, the BMW 323i enjoyed cult status with sports oriented drivers. Tuners, fitters and conversion specialists alike were in great demand and virtually all suppliers were involved with this BMW 3 Series top model. Along with the revised four-cylinder engines, a new entry-level model, the BMW 315 with 55 kW/75 hp, was added to the range during the second half of the life cycle.
Source: BMW press