There are some new cars you know are in the pipeline which are really imperative to drive long before they go on sale. Customers know they are coming and anybody with a motoring soul wants to know just how good these new high profile cars are well before they go into the showrooms.This is now the third generation of the premium medium sized, four seat Coupes from BMW and the previous two have all been highly rated by the motoring pundits of their time. BMW say they created this market segment way back in 1992 and it is segment leader for sales by a large margin, although there are not too many competitors. The Mercedes CLK is the main opposition and that too is a fine car.Audi to date have not really been in this market segment but the new and larger TT Coupe has changed all that, although it is no match for passenger space for either the BMW or Mercedes Coupes.A new 3 Series Coupe is always a notable addition to our must-drive cars list. Unfortunately I was away on holiday for the press launch of the new Coupe but to coincide with the UK on sale date of 23 September BMW whistled a car to me and it didn't take many hours before car enthusiasts and BMW owners in the know spotted the new Coupe on the road.For the record BMW say they will have around 4,000 of these new Coupes for sale until the end of this year and peak sales in the UK will be around 13,000 units in a full year. BMW also expect the new generation Coupe to repeat its penetration of up to 25 per cent of total 3 Series UK sales. A high proportion of customers are business professionals with over 35 per cent being directors or executive managers and nearly 20 per cent are business owners. BMW's customer demographics also show that 82 per cent of customers are male and the average income of an owner is £75,000.Five models are currently available of the new 3 Series Coupe and more will follow next year including smaller four-cylinder petrol and diesel engines and an even higher performance M version. Rumours suggest there will be folding metal roof coupe/cabriolet variants introduced next year as well. Currently there is just one level of specification, SE, but again more will follow. Needless to say there is a wide range of extra cost options.The five models we have at launch are all powered by straight six-cylinder engines - three petrol and two diesel units with prices ranging from £28,090 up to £35,475.When launching a new range it is customary for BMW to introduce a new engine or two at the same time. This time it is the new 335i, a 2,979cc direct injection petrol unit with twin turbochargers, the world's first straight six with Twin Turbo technology. This unit produces 306hp and a massive 400Nm of torque giving the Coupe a 0-62mph time of 5.5 seconds and a top speed limited to 155mph. BMW say by using smaller twin turbochargers rather than one large heavy unit, and a straight six unit with an aluminium crankcase over a conventional V8 engine with similar power and toque outputs, the power to weight ratio of this new unit saves 70kg in weight.For the record the other four engines currently on offer are: 330i - 272hp, 325i - 218hp petrol units and 335d - 286hp and 330d - 231hp diesel units. All models, except the 335d Coupe, are fitted as standard with a six-speed manual gearbox. A new six-speed automatic transmission is available as an option, but it is fitted as standard to the 335d Coupe.The new Series Coupe is styled more differently from its saloon counterpart than ever before. It is not a saloon with a sloping rear roofline and two doors. Virtually all the body panels are different from those used for the still relatively new saloon models. It retains BMW's classic Coupe styling theme of a long wheelbase and bonnet with of course drive to the rear wheels. Muscular rear wheel arches together with the now familiar new low profile face and low stance of BMW with short front and rear overhangs make this a very purposeful looking machine. A near perfect 50-50 weight distribution balance is achieved with this design and layout.The interior dimensions of the new Coupe are slightly larger than the range it replaces. It is 92mm longer in overall length giving more leg, head and shoulder room and more boot space. It may be bigger and have more equipment but the new Coupe is 10kg lighter than its predecessor. The extra space inside the new Coupe is much appreciated and four adults can be accommodated easily, it is a genuine four seater Coupe, not a two plus two.So there in a nutshell we have what the eagerly awaited new BMW 3 Series Coupe is all about but apart from the stunning looks this Coupe has so much more to offer. The model I tested had the new 335i straight six, twin turbocharger, petrol engine with the six-speed manual transmission. Whilst this will certainly not be the main selling derivative in the long term, until the M version arrives, this will be the model the Media will be talking a writing about.The performance from the engine is stunning, not just for top speed or acceleration, it just feels so strong and responsive right through the rev range and it has a wonderful twin exhaust note that is nowhere near so tiring and intrusive as the howl of the 3.2-litre V6 unit used in the new Audi TT.Although the maximum 306hp is produced at 5,800rpm the engine will run without stress up to 7,000rpm underlining its smoothness and refinement. But the hero figures relate to torque. Four hundred NM or 295lbs ft, of torque is available from just 1,300rpm and maintained until 5,000rpm. This very wide band of power makes the car so flexible to drive unless you are in a hurry fifth gear can be used most of the time except when cruising at high speeds. On typical British A roads it allows the driver to overtake slower moving traffic with effortless ease, no stress, no running out of power, no white knuckles and no frantic cutting up of other road users. It makes fast and safe driving effortless. It is a real 'storming' engine yet very refined and ideal as a fast cut and thrust machine or relaxed and responsive as a long legged cruiser. The fuel economy is shown in official figures as 29.7mpg but my test car returned 25.4mpg.Briefly reviewing other aspects of the new Coupe. The ride is on the firm side but the payback is that road holding is superb and the grip and composure is outstanding. Of course BMW's Dynamic Stability Control is fitted as standard. My test car had the optional 18-inch wheels over the standard 17-inch units and there was a suggestion that this does cause the Coupe to follow the tramlines created by heavy lorries.. I might just stick with the standards wheels and runflat tyres for optimum driving refinement.Behind the wheel it is easy to get just the right driving position although the clutch pedal is a little to close to the footrest until you get used to the positioning. The SE specification gives you everything you would expect and the instrument layout is simple and logical. Only the BMW iDrive control remains a 'thorn in the side'. The test car had a whole host of extras including leather upholstery and satellite navigation, to name but two items. In total the extras added to this test car raised the standard price of £33,420 by a further £5,065.Yes the new 3 Series Coupe can be expensive but it has the quality to justify the price and it worth paying that much just to get the wonderful new 335i engine in a stunningly appealing premium mid sized Coupe.MILESTONES:BMW 3 Series 335i SE Coupe.Price £33,420 (as tested £38,485).Engine: 3.0-litre, straight six, twin turbocharged, direct injection petrol, 306hp with 400Nm of torque from 1,300rpm.Performance: 155mph (limited), 0-62mph 5.5 seconds, 29.7mpg (25.4mpg actual),CO2 228 g/km. VED, Band G £210.For: Fantastic new 335i engine, high power and torque, superb handling, roomy interior for four adults, eye catching styling.Against: Could be considered expensive if fitted with lots of options, iDrive is fiddly as always, 18-inch wheels look great but 17-inch might prove a better overall drive.