We can finally bring you full details of the new BMW 3 Series Coupe due to go on sale in Britain in September this year. Not only does the new Coupe distance itself from the 3 Series Saloon and Touring in terms of styling, it also signals the launch of BMW's first ever twin-turbocharged petrol engine.

BMW's pictures reveal that the new 3 Series Coupe treads a fine line between sporty and elegant. At the front, the headlights and bumper are a new design, though similar to the Saloon and Touring. In profile, the new Coupe appears long and sleek, though the rear overhang looks quite lengthy. The new design of rear light disguises some of this bulk, but these actually look a little bland, at least in these preliminary pictures. It is likely that the subtle sculpting will be more appealing in the metal and the lights now feature a horizontal row of LEDs, which should ensure they stand out. All photographs are of the new 335i model, though it is expected that all six-cylinder models will be fitted with the distinctive twin-exit exhaust.

At launch there will be just two models to choose from. The 325i SE Coupe will cost £28,090, with the 335i SE Coupe coming in at £33,420 on-the-road. First up is the 325i Coupe powered by the same 2.5-litre straight-six we tested in the 3 Series Touring last year. BMW claims a 0-62mph time of 6.9 seconds and a top speed of 153mph. Combined cycle fuel economy is 33.6mpg.

Making the headlines though is BMW's all-new twin-turbo inline six-cylinder engine powering the 335i model. Despite the tag, this unit has a swept volume of just three litres. In the Coupe, the rated power output is 306bhp, with peak torque at 295lb.ft. The raw figures are impressive enough, but thanks to the addition of a small (and therefore quicker reacting) turbocharger per three cylinders the peak torque figure is available all the way from 1300 to 5000rpm, which should endow the 3 Series Coupe with serious in-gear pace across country. The 0-62mph time is claimed to be 5.5 seconds. The 335i's engine also utilises direct injection, which allows a higher compression ratio, releasing more torque and increasing the engine's efficiency. BMW claims that the 335i Coupe delivers 29.7mpg on the combined fuel economy cycle. No CO₂ emissions data is available as yet.

Inside, the new 3 Series Coupe promises to be a comfortable four-seater, with only detail changes to the regular 3 Series interior. Occupants sit lower than in the Saloon and Touring giving the car a sportier feel and acceptable headroom despite a lower roof. A new feature to the Coupe is a feeder arm built into the B-pillar that 'hands' the seatbelt to the front seat occupants.

Future models include a 320i and 320d alongside the 330i Coupe with a 272bhp version of the 3-litre straight-six. This car will hit 62mph from standstill in 6.1 seconds. One of the most interesting models will be the 330d Coupe, with a six-cylinder diesel engine pushing out 231bhp and a massive 369lb.ft of torque. Though its 0-62mph time of 6.6 seconds is beaten by the petrol model, its 43.5mpg on the combined cycle will endear it to drivers in these days of inflated petrol prices. There is no word of the new M3 as yet, but be patient; it's on the way.

Shane O' Donoghue - 24 Apr 2006