BMW has a new flagship coupe in Australia, where first deliveries of the third-generation 6 Series two-door hard-top are expected to almost double sales of the top-end model line later this month.

The second instalment of BMW’s redesigned 6 Series range, which follows the previous coupe and convertible models launched in 2003 and the original 635 CSi of 1981, follows the release of the new 6 Series Convertible here in August.

The 6 Coupe follows the convertible in being bigger and heavier, yet prettier than before, while the all-new 6 Series Gran Coupe that completes the line-up here in the third quarter of next year features four doors and is longer again.

Like the convertible – sales of which are up 62.5 per cent so far this year, the coupe rides on a 75mm-longer (2855mm) wheelbase and is 74mm longer overall (4894mm), as well as 39mm wider (1894mm) and 5mm lower (1369mm).

Along with improved side impact safety and 53 per cent better torsional rigidity, that makes the 6 Series Coupe 120kg heavier than before at 1770kg, which is still lighter than the convertible.

Described as a low-volume, high-cachet model that “pulls together everything we do best”, BMW expects the new 6 Series Coupe to be its most popular ever, in part because – like the convertible – it is available in two non-M variants for the first time, including the 235kW/450Nm twin-scroll turbocharged 3.0-litre 640i.

As we’ve reported, the 640i lowers the admission price to BMW’s 6 Series Coupe club by almost $50,000 – and undercuts the equivalent 640i Convertible ($194,300) by $16,000 – with a price of $178,300 plus on-road costs.

However, the replacement for the only previous 6 Series Coupe variant – the V8-powered 650i ($227,300) – will be $5000 more expensive than before at $232,300. Extra standard equipment for the 650i includes ventilated front seats and the Surround View camera system.

BMW says that makes its new 6 Series Coupe line-up a direct rival for the Mercedes-Benz SL (from $237,000) and CL (from $330,500), as well as Audi’s R8 (from $268,500) and a host of established Italian sportscars from Maserati, Ferrari and even Lamborghini.

However, it also makes the latest V8-powered 6 Coupe pricier than Porsche’s new 911 (from $229,900) and Jaguar’s latest XKR (from $219,000), although the respective S and XKR versions of those exotic coupes cost more again, at $239,000 and $263,100.

For the money, the 6 Coupe adds a fixed roof but comes with the same exterior two-door design as the convertible, dominated by the same forward-inclined ‘shark nose’ kidney grille and also including a lower, more rear-set glasshouse, wider L-shaped tail-lights and a concave bootlid lip.

Like the convertible, the coupe’s engines are mounted 7mm further back, resulting in perfect 50/50 front/rear weight distribution, while boot space grows by 10 litres to 460 litres, aided by an optional ski-port.

Inside, there is a new driver-focussed cockpit design highlighted by a double-stitched leather feature that runs diagonally across the centre console, the largest (10.2-inch) in-dash monitor in its class, and the option of a full leather instrument panel.

BMW says that with a 0-100km/h acceleration time of 5.4 seconds, the 640i Coupe is as quick or quicker than the SL350, SL500 and XK (but not the CL500), while being more efficient than all of those models at 7.8L/100km.

The 300kW/600Nm 4.4-litre twin-turbo V8-powered 650i, meantime, is said to be quicker (0-100km/h in 4.9 seconds) than all of its rivals while being more efficient (10.6L/100km) than all but the SL350.

Both engines come standard with an eight-speed (up from six-speed) ZF automatic transmission, and both models are fitted with ‘Driving Experience Control’, which offers four levels of engine and transmission response, accelerator pedal progression, electronic stability control response and electronic power steering (EPS) assistance.

The latter can be had with the option of Integral Active Steering, which combined a speed-dependent variable-ratio steering system with rear wheels that can turn by up to 2.5 degrees – in the same direction as the front wheels to improve stability or in the opposite direction to aid manoeuvrability.

Apart from the new EPS system and eight-speed auto, other standard fuel-saving technologies within the EfficientDynamics suite include idle-stop, brake energy regeneration and – for the entry-level 640i at this stage only, Air Vent Control and Eco Pro, which maximises electrical system efficiency, coaches drivers to be more fuel-efficient and displays how much fuel has been saved by doing so.

Adaptive LED headlights are optional for the first time in any BMW ($2800), as is a Bang & Olufsen 16-speaker 1200-Watt sound system with LED-illuminated floating aluminium speakers, priced at $16,000 with the 640i and $14,000 for the 650i.

Both 6 Series Coupe models come standard with a Harman Kardon audio system, adaptive bi-Xenon headlights, LED foglights, LED daytime driving lights, heated sports seats, a glass sunroof, Professional navigation, voice-recognition, BMW’s second-generation full-colour head-up display, High Beam Assist, rear-view camera, front/rear parking sensors, cruise control with auto brake function, Bluetooth/USB phone connectivity, metallic paint, keyless entry/starting and 19-inch alloy wheels.

Apart from a V8, the 650i adds Adaptive Drive with Dynamic Damper Control and Dynamic Drive anti-roll system (normally $8000), bi-colour 19-inch alloys, soft-close doors, comfort seats, Professional HiFi system, TV, Surround View and front seat ventilation.

An M Sport package will be available for both new 6 Series Coupe models from launch – and for the 6 Series Convertible by late December – priced at $7500 (650i) and $8700 (640i).

The M pack comprises a bodykit including more aggressive front and rear bumpers and side skirts, 20-inch wheels, Anthracite headlining (not on the convertible) and, for the 650i only, an enhanced exhaust note.

Expect both 6 Series two-door models to be crowned next year by a piping-hot M6 model powered by a version of the upcoming M5 sedan’s 412kW/680Nm twin-turbo V8, around the same time the Gran Coupe joins the 6 Series range.