For the first time the M4 Coupe and M3 Saloon models have been launched - it's the fifth generation - with individual model names in deference to the different model series that provide their basis.Another first is the adoption for this BMW M model of the high-revving, three-litre six-in-line engine with M TwinPower Turbo tech specifically developed for this purpose and capable of 321kW and 550Nm across a very wide rev range starting at 1850rpm.That exceeds the outgoing BMW M3 by roughly 40% - but still the new engine claims a reduction in fuel consumption and emissions of around 25% thanks in part to shedding more than 80kg through using more lightweight materials – much of it saved by a carbon fibre-reinforced plastic roof.ESSENTIALLY THE SAMEBMW M engineers also paid close attention to aerodynamic performance and incorporated the latest Active M Differential among many other technical highlights. During the development process the engineers worked closely with BMW Motorsport’s professional racing drivers who did extensive testing and set-up work on the Nurburgring Nordschleife.2014 BMW M3 Saloon image gallery2014 BMW M4 Coupe image gallery The new M3 sedan and M4 Coupe – essentially the same car with rear-wheel drive but the latter with a coupe shell - are formed, BMW says, “from a host of finely blended elements, all working in perfect harmony to deliver outstanding performance, precision and agility on road and track”.The design, the automaker adds, “sought to channel air around the car in the quest for ultimate performance while also ensuring the engine, powertrain and brakes received the requisite cooling, even on a track”.The assertive front apron, smooth underbody and lip spoiler at the rear of the M3 (boot-lid spoiler on the M4 Coupe) reduce lift equally front and rear “to the benefit of handling”. Albert Biermann, development head at BMW, said: “The way we channel air through the oil cooler creates a venturi effect which reduces front-axle lift and so improves steering.”POWER UPGRADEWhatever the cars look like, however, it’s the aluminium and steel under the bonnet that counts and here there’s a return to the classic six-cylinder in-line engine as used on the second and third generations. The first was a 2.5 straight-four that made (by today’s standards only 190kW) and the fourth a 309kW/400Nm non-turboV8....The latest engine has a slight power upgrade over the previous V8 to 321kW, now delivered from 5500 -7300rpm with max revs set at an unusually high (for a turbo engine) 7600rpm. Peak torque, however, has grown by about 40% to 550Nn over a very wide 1850-5500rpm.All that translates to 0-100km/h in 4.3sec (manual) and 4.1sec (auto) for either car with top speed limited to 250km/h. Despite the turbos, the engine’s fuel consumption (over the EU cycle) is as low as 8.3 litres/100km, emissions as low as 194g/km – each an improvement of more than 25% over the previous V8.It all sounds good, too, with BMW continuing the practice of electronically controlled flaps in the twin-pipe exhaust system that produce a sound that’s striking and unmistakable over the entire engine speed range.The different selectable drive modes, programmable through an MDrive manager and activated via the iconic steering-wheel ‘M’ buttons, offer drivers a choice of pre-configured and balanced vehicle set-ups which also feature different engine sound profiles.'SPRINTING PERFORMANCE'The standard transmission is a smaller and12kg-lighter six-speed manual with a robust double-plate clutch. The gearbox blips the throttle on downshifts - previously a feature reserved for the M Double Clutch Transmission - improving the smoothness of the driving experience and helping to enhance stability.The option is a seven-speed, third-generation, M Double Clutch Transmission with Drivelogic and Launch Control. As well as auto changes, manual mode can be invoked for ultra-fast gear changes with no power interruption. “Launch control,” BMW says, “ensures optimum sprinting performance off the line, producing acceleration figures that would be simply unattainable with the manual gearbox.”Also included is “stability clutch control”: it opens the clutch if the car understeers to bring it back into line and Drivelogic that, BMW explains, gives the M3 and M4 more comfortable and economy-focused or even sportier characteristics depending on what the driver wants.Seventh gear is intended to save fuel on high-speed cruise.INSTANT ADJUSTMENTS“The ‘Active M Differential’,” BMW says, “makes a considerable contribution to the superb dynamics of the new cars. It uses an electronically controlled multi-plate limited-slip differential to optimise traction and directional stability.“Working precisely and rapidly, the control unit links up with the dynamic stability control and takes into account the position of the accelerator, the rotational speed of the wheels and the car’s yaw rate.“Every driving situation is precisely analysed and an impending loss of traction on one side of the car is identified early. The degree of differential lock – which may be anywhere from zero to total – is adjusted as required in a fraction of a second. Wheelspin is prevented on slippery surfaces in instances where the rear wheels have widely differing friction co-efficients or in tight bends and when changing direction with particular vigour.”Both cars have 19” grey or black (UK standard) alloy rims and aluminium is used for the front wings and bonnetThe cabin has an emphasis on even more sporting ambience but with now traditional BMW M equipment details: M door sill finishers, M gearshift lever, M design circular instruments with white graphics, M leather steering-wheel (with M logo, chromed trim and iconic triple-colour contrast stitching) and metallic shift paddles (if M DCT gearbox specified).CONTOURED SEAT-BACKSThe front seats are full buckets with a single-piece back panel and high adjustable side bolster, the main adjustments powered. Stitching, upholstery segmentation and perforation lend the seats a slim-fitting feel, the BMW M logo on the seat is, for the first time, illuminated.The contoured uprights of the rear seats, BMW adds, also offer exceptional lateral support and can be luggage-folded in a conventional 60:40 split – a bonus missing on many sports-orientated cars.Both cars come with an extensive list of standard equipment: adaptive M suspension, 19” M alloy rims, heatable and powered BMW M seats, folding exterior mirrors, glossy Shadowline exterior trim and the full BMW Professional audio package with upgraded Bluetooth.The list of options is even longer: a free BMW M Laptimer app which allows owners to analyse their personal driving style and records speed, longitudinal and lateral acceleration, engine revs, gear choice, steering angle, accelerator position and fuel consumption.The data can subsequently be analysed via graphic displays on the customer’s smartphone, including the driver’s reactions. Another feature allows two recordings on the same circuit to be compared corner-by-corner: the readings can be either the driver’s own or data shared via email.A LITTLE HISTORYThe first generationIt was at BMW Motorsport’s HQ in Munich, 28 years ago, that the company’s then managing director Paul Rosche developed the idea for the BMW M3. Production began a few months later at the original BMW plant next door. Today, almost 23 years later, production is back there.It was in early 1985 when BMW Motorsport began development of a new machine to compete in Touring Car racing. The road-going version required for homologation - 5000 had to be built to satisfy the sporting regulations - was conceived from the outset as a race-ready Group A machine. The 2.3 four-cylinder model made its debut in the middle of 1986 and today would be out-accelerated by many hot hatches: 0-100 in 6.8sec, top speed 230km/h.17 970 had been sold worldwide when production ceased in 1991.The second-generation.Its successor was not designed as the basis for a race car and came as a two-door coupe, convertible and four-door sedan. A six-cylinder, three-litre, 213kW engine powered all three to sub-six 0-100 times and top speed went up to 250km/h. A short-run 219kW M3 GT variant was added to the range in 1994; 1995 saw the engine grow to 3.2 litres, power to 240kW.In 1997 the M3 became the world’s first volume-produced car to be available with a Sequential M Gearbox (SMG). This transmission was based on the conventional gearbox for the M3 but with a clutch that was activated electro-hydraulically.71 242 units of the Coupe, Convertible and Saloon combined were produced.The third-generation.The third-generation arrived in 2000, Coupe or Convertible, six-cylinder still 3.2 litres but now making 256kW and reaching 100km/h in 5.2sec. New were a variable diff lock, second-generation SMG and shift paddles.Pinnacle of this generation was the M3 CSL (2003) - Coupe Sport Lightweight. Carbon-fibre roof, centre console and door panels, and the omission of numerous comfort features. It weighed 110kg less than the standard M3 and all 1383 units of the 268kW car sold in a few months.The fourth-generation.It was 2007 and in came an all-new, four-litre, 313kW/400Nm, V8 - the first time an M3 was without the now classic straight-six. Coupe, sedan and convertible eventually arrived. Carbon-fibre strengthened plastic roof, power dome on the aluminium bonnet, aluminium chassis parts.Eventually an M3 GTS morphed from the original: 4.4 V8 making 335kW, special chassis, two-seat cabin for track use and only painted orange. Only 135 were delivered.