ONE thing that's guaranteed to make the hearts of enthusiasts sink is news that a car maker plans to put a small engine in its large sports car.

The exercise usually smacks of a huge compromise - in a bid to save some cash by offering a few less cubic centimetres, a once-acclaimed GT is now a shadow of its former self.

The classic move is to offer a modest six-cylinder engine alongside a more potent V8 motor.

The latter usually sounds superb - all bark and plenty of bite - while the former fails to stimulate the senses and lacks the oomph to justify the cash outlay, and its existence.

So if I tell you that BMW has done just that with its 6 Series, you'll probably have branded the German firm's six-cylinder offering a loser before finishing this sentence.

To do so would be a mistake, as the 3.0-litre engine under the car's bonnet is far from average.

Judging by the number of cars on the road, the 6 Series (pictured below) has confounded the critics.

There's no question that its looks are challenging. However, a GT of this stature shouldn't be allowed to blend into the background. You buy something like the 6 to make a statement, be it about your wealth or your personality.

Get your head around that and the car starts to make sense. Part Bang and Olufsen television on wheels, part unapologetic trophy purchase, the moment you fire up the car's deep-chested 4.4-litre V8 engine you know the experience is going to be special.

Hang on a minute - what about the car's "other" six-pot motor? That's special too, but in a different way.

The heart of any car is its engine, and BMW has been churning out some clever units of late, such as its Valvetronic petrol motors and a clutch of impressive diesels.

While oil burners might be taking over the world by stealth, there's plenty of life left in unleaded-fuelled engines.

BMW's super-duper lightweight six-cylinder unit that powers the 630i is a perfect example.

Constructed of hi-tech materials such as magnesium and aluminium, it punches well above its weight in horsepower terms and infuses the 6 with a more excitable personality.

The great gobs of torque available from the 645i's V8 have been replaced by a racecar-like urgency from the 630i's six-cylinder motor.

From the fractionally higher-frequency idle to the obvious snappiness of the throttle, it's clear that this 6 prefers to scream its way to your chosen destination - not rumble like the V8.

And so it proves that any enthusiastic excursion in the 630i is akin to holding onto the tail of a feline with a burnt bottom.

The engine has three settings: town, howl and shriek. The first is self explanatory and perfect for when popping to the shops.

The second and third settings differ only in that the former is for when the road is relatively straight and the latter when twists and turns require more frequent and generous prods of the throttle pedal.

Some people may be put off by its styling, but you can't fail to be impressed by the 6's ability to go, steer and stop.

The steering is full of feedback, the manual gear-change is light and slick, while the way it can be hustled from bend to bend is nothing short of remarkable as the car shrinks around you and behaves like something half its size.

Much fun can be had with a 630i in standard trim, but if you must spend money on optional extras there are only two you need to know about - Dynamic Drive and the six-speed auto gearbox.

Dynamic Drive enables the car to corner almost flat regardless of how fast you pile into a corner.

Great for handling, this "active ride" feature also increases occupant comfort as you're not being flung from side to side.

The auto 'box adds another motorsport-inspired layer to proceedings, allowing you to nudge the gearlever fore and aft in sequential mode in good time for a bend or to help you race towards the redline when accelerating hard.

After an enthusiastic blast in the "baby" 6, it's hard not to like the car.

For a BMW it's a surprisingly extrovert model.

The sound of the engine, the car's poise and behaviour on the road, its keenness to go where you point it - they are all fabulous attributes. All in all, a pleasant surprise.

For details, call Woods BMW on 01256 703703.