If you're a fan of mid-sized sports coupes, chances are you're a fan of BMW.

The two go hand-in-hand to such an extent that BMW is far and away the leader in this market, which means the launch last weekend of the new 3 Series Coupe was pretty significant.

Five new models were unveiled, all powered by straight-six cylinder engines. To the casual admirer, there won't be much difference between the old and new, but in fact there are some pretty impressive improvements.

Let's start with the styling. It is a larger and more spacious model, but hides the extra bulk under a sleeker, smoother body.

It's also a more potent-looking beast which has a far more aggressive style than the already-impressive 3 Series saloon. It has a sportier nose with air dams and the almost obligatory mesh, plus some deep side skirts.

It's under the skin, however, where the most important tweaks and polishes have been carried out. They are designed to make this the ultimate sports coupe and keep its few rivals at bay.

BMW, which claims to have created this mid-range coupe market in 1992, expects to sell around 13,000 new 3 Series Coupes a year. Sounds quite modest to me, especially when you consider this new range includes some high-end luxury, technology and impressive engines. This is more than just a two-door version of the 3 Series saloon, and you could easily spend more than £33,000 on less competent rivals.

This is the third incarnation of the 3 Series Coupe, but BMW claims to have a tradition of four-door coupes stretching back to 1937. And they say the aim has always been the same: graceful elegance and sporting driving behaviour.

At the heart of the test version is a new engine, the world's first straight-six with twin turbo technology. Rather than one large turbo it has two smaller units which allow the boost to be built quickly, eliminating turbo lag. The real advantage is low power-to-weight ratio. To achieve such torque with a normally aspirated engine would require a 4.0 litre V8, but by using the twin turbo system it saves 70kgs.

It means the car has electric performance, zipping to 60mph in 5.5 seconds, yet it returns a very reasonable near-30mpg on a run.

BMW have always been innovators and some of the ingenious features on this car are worth recording. It has a lighting system in which you can select main beam which dips automatically if it sees' oncoming lights. This way you avoid blinding other motorists. On the way back from France, I found this system to work incredibly well. It simply dips for a few seconds, then resumes full glare as soon as the oncoming car has passed.

It also has a new upgraded automatic gearbox which allows for faster switches between cogs than on a traditional automatic system.

The 3 Series Coupe is relatively expensive, but such is its appeal customers come from a broad cross section. Some 29 per cent are 30 to 39; 28 per cent are 40 to 49; and 29 per cent are 50 to 59. It is a car which appeals predominantly to men (82 per cent).

PRICE: £33,420 The range spans £28,090 to £35,475.

ENGINE: A 2,979cc unit generating 306bhp.

PERFORMANCE: Top speed 155mph, 0 to 60mph in 5.5 seconds.

COSTS: Urban, 20.5mpg; extra-urban 40.4mpg; combined 29.7mpg.

EMISSIONS: 228g/km.

WARRANTY: Three years, 60,000 miles.

INSURANCE: Group 18.

All T&A road test vehicles are independently selected and assessments are carried out impartially by members of our own staff who base their opinions only on the vehicle supplied for these purposes by the manufacturer.