In 1989 the 6 Series was supplanted by the 8 Series, but in late 2003, the 6 Series was reintroduced as a 2004 model, with coupe and convertible versions based on the BMW E63 and BMW E64 platforms, respectively. These two models are each available with either a 3.0 L (2996 cc) straight-6 making 190 kW (258 hp DIN) at 6600 RPM and 300 Nm (221.3 ft.lbf) of torque from 2500–4000 RPM (in the 630i) or a 4.4 L (4398 cc) V8 making 245 kW (333 hp DIN) and 450 Nm (331.9 ft.lbf) of torque at 3600 RPM (in the 645Ci). In some markets, the convertible versions are sold as the 630i Cabriolet and the 645Ci Cabriolet.
The V8 in the 645Ci is the N62 engine, the same powerplant used in the 545i and 745i, with BMW's Valvetronic variable valve timing system. This is an all aluminum engine with 4 valves per cylinder. This 6-Series comes with either a 6 speed automatic transmission or a 6 speed SMG sequential gear box. For the 2006 model year, BMW renamed the 645Ci as the 650i. The reason for this change was the increase in engine displacement.
Unlike that of the new 5 Series and 7 Series models, the styling of the new 6 Series has generally received a warm welcome from the BMW community—except, largely, owners and enthusiasts of the E24. The new 6 Series was designed to look like a shark, and really does remind you of one. The controversial "Bangle-butt" rear styling works somewhat better on the shapely E63 than on other BMWs.
In 2005, an M6 version of the new 6 Series was introduced. It shares the E60 BMW M5's engine and transmission (507 bhp)