ONCE a year the Society of Motor Manufacturers and Traders allows the country's motoring press the chance to try a whole range of cars on and around the Millbrook test track facility.

Rover 45 iXL 1.8 LPG

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WITH most LPG conversions, there is little if anything in it for the driver. Occasionally, lower carbon dioxide emissions point to a smaller benefit-in-kind (BIK) tax bill, but when the extra expense of the LPG conversion is taken into account – which must be included in the BIK price for in-house conversions – then a company car driver might take some convincing to be persuaded to go 'green'.

However, the sudden puff of gas as the LPG nozzle is released from the vehicle at the filling station should be music to the ears of any fleet executive.

MG Rover – freed from the shackles of its BMW Group owners a few years ago – decided to go down the LPG conversion route through its sister company Powertrain, and a wide range of vehicles are now available for factory- approved conversion.

The Rover 45 iXL 1.8 is one such vehicle and while some might argue that its packaging is out of date, it certainly looks distinctive when compared to the increasing number of generic Euro-boxes we see on the roads today. Those opting for the Rover 45 are bound to notice a reduction in fuel expenditure thanks to LPG's pump price advantage, but will see little difference in BIK payments over the year.

There is no difference in CO2 emissions between the petrol and LPG versions, generating 174g/km. The 1% discount in BIK from 18% to 17% for the LPG hardly affects annual tax payments.

Opting for the petrol version generates a £563.31 BIK bill for a 22% tax-payer annually, compared with £614.10 for the same tax-payer driving an LPG conversion – a difference of £4 or so per month. The BIK tax bills are higher for LPG because the cost of conversion – £2,195 in this case – is added to the P11d price. This is reduced for the fleet operator though, by the 60% rebate from the PowerShift grant, bringing the cost down to £878 for the LPG conversion.

Initial impressions are that the car has great seats, is comfortable and would make an ideal long distance companion. Its combined fuel economy of 38.9mpg is also relatively pleasing for a 1.8-litre, although we expect this figure to be lower when run solely on gas.

The Rover 45 holds the road well, benefiting from recent chassis improvements. The steering is direct and gearshifts are smooth. In fact, as is the case with so many modern gas-powered cars, for most of the time we couldn't tell which fuel we were using from the car's performance.

However, once on the high-speed bowl with speeds of 100mph, it was a different story. The Rover seemed a little sluggish under hard acceleration and a quick switch to petrol seemed to release a little more torque.

In terms of specification, our well-equipped XL model was loaded. As standard it has an electric sunroof, parking sensors, CD/radio, 15-inch alloy wheels, electric front windows, traffic alert system, electric door mirrors and air conditioning with pollen filter.

It seems the green transport arena has been joined by yet another worthy alternative to petrol.

Model Rover 45 iXL 5-door, LPG
Engine (cc): 1,796
Max power (bhp/rpm): 115/5,500
Max torque (lb-ft/rpm): 118/2,750
Max speed (mph): 121
0-60mph (sec): 9.3
Fuel consumption (mpg): 38.9
CO2 emissions (g/km): 174
BIK tax 2003/04 (22% tax-payer): £564.85
Transmission: 5-sp man
On sale: Now
Price (OTR): £14,395

Daihatsu Charade 1.0

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TOUTED as the world's most efficient petrol engine, the Daihatsu Charade 1.0 litre three-door supermini gives some of its rivals a run for money in terms of economy and performance.

More than £600 less expensive than the cheapest Ford Ka, with only the Perodua Kelisa and the Fiat Seicento undercutting it on list price, the Charade, at £5,995 on-the-road, is in line for most budgets.

It replaces the Cuore which was only offered as a five-door. The new Charade revives a Daihatsu name from the past and comes in either three or five-door guise.

Despite only having a 1.0-litre three-cylinder engine, it doesn't feel slow and performance wise it is easily on a par with a 1.3-litre Ford Ka. It also feels a lot nippier than mainstream superminis with this kind of power.

For £5,995, the spec list is impressive with anti-lock brakes and electronic brakeforce distribution (EBD), driver and passenger airbags, central locking, electric front windows and door mirrors and a radio/CD player.

For those able to spend a little more, the £6,995 model also has side airbags, alloy wheels and air-conditioning. Driving-wise, it makes a perfect city car, excellent for nipping about town. As well as being illegal, the thought of driving this car at nearly 100mph is made unappealing by the noisy engine, despite a new engine mounting designed to keep noise, vibration and harshness (NVH) levels down. It handles corners well and its lightweight body means there is no sluggishness despite its small engine capacity. The interior did seem a little cheap when compared to some mainstream rivals, with shiny surfaces and hard, brittle plastics, but on the plus side is a standard CD player and electric windows and mirrors.

In terms of economy, the Charade excels. It produces an impressive combined mpg of 58.9 and CO2 emissions of 114g/km. That means a 22% tax-payer will only pay £194.53 benefit-in-kind (BIK) tax over the year for 2003/04.

The Charade is designed for the realms where a car is only needed to transport one or two people from A to B and it would be easy to criticise it for feeling cheap. But bearing in mind its rock bottom price, such criticism would perhaps be unfair.

Model Daihatsu Charade 1.0
Engine (cc): 989
Max power (bhp/rpm): 58/6,000
Max torque (lb-ft/rpm): 67/4,000
Max speed (mph): 99.4
0-60mph (sec): 12.2
Fuel consumption (mpg): 58.9
CO2 emissions (g/km): 114
On sale: now
Price (OTR): £5,995

Audi S4 Avant

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IT has been said so many times that it has almost become a cliché, but 'understated elegance' is something Audi excels at.

With perhaps the exception of the TT, Audi could never be accused of making a brash looking car – and this is the case with the latest high-performance model to join its range.

Two years after the latest A4 arrived on the scene, Audi has unleashed variants with the coveted 'S' prefix.

Up to now the most powerful version of the latest A4 used a 217bhp 3.0-litre.

However, the flagship model – badged S4 – is now on sale, boasting a 4.2-litre V8 engine with 339bhp and 302lb-ft of torque. Unlike BMW, whose M3 is only available as a coupe, Audi offers the S4 in both saloon and Avant variants like AMG versions of the Mercedes-Benz C-class which comes in saloon and estate guises. However, other than a discreet S4 badge on the grille and the aluminium-faced door mirrors, there are few clues to the car's potential.

Previous S4s came with a twin-turbo 2.7-litre six-cylinder engine, but those who believe turbo technology is akin to a silicone enhancement will be pleased to know the 4.2-litre V8 in the new model is naturally-aspirated.

Carbon-fibre fetishists will delight in the interior of our test model, which had seductive lacquered carbon fibre inserts in the dashboard and doors. This feature is standard, although aluminium is also available, as are two different wood finishes.

The seats are a combination of black leather and light grey alcantara, while the rest of the interior is standard A4 with logically presented instruments and switchgear. The V8 engine is quiet when idle, but on the move the rumble from the exhausts hint at the car's true potential.

Step on the gas in just about any of the six gears and the S4 will pick up speed without fuss, although with much greater urgency in the first four gears. The burbling engine note turns into a roar and becomes increasingly addictive. Don't expect to improve on the 21.0mpg official combined fuel consumption figure, even when fully complying with the law.

The S4's weighty steering offers enough feedback to let you know that in most circumstances the tyres will not be parting company with the road surface. Grip levels are absurdly high and the four-wheel drive system ensures there is always traction, even on wet roads.

Audi would argue that with power outputs climbing higher all the time, the best way to harness them is by driving all of the wheels. Driving purists would disagree, but even with the corrupting influence of drive through the front axle causing a tendency to understeer, few cars with this kind of power feel as safe and as surefooted as the S4.

Model: Audi S4 Avant
Engine (cc): 4,163
Max power (bhp/rpm): 339/7,000
Max torque (lb-ft/rpm): 302/3,500
Max speed (mph): 155
0-62mph (sec): 5.8
Fuel consumption (mpg): 21.0
CO2 emissions (g/km): 322
On sale: now
Price (OTR): £37,280

Citroen C3 1.6 Exclusive Sensodrive

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CAR manufacturers seem to have spotted a marketing opportunity for the Formula One-style gearchange.

It is 13 years since Ferrari introduced the steering-wheel-mounted gearshift and while high-performance road cars have tried to mimic the F1 experience, they now seem to be more common in the supermini sector.

While some offer no-nonsense stickshift sequential manuals like the Vauxhall Corsa Easytronic, Citroen is keen to draw attention to the fact its range-topping C3 can be specified with this type of transmission with a 'paddle' gearshift for £200 more.

The benefit for drivers of the proper sequential manuals is they come without a clutch pedal and have a fully automatic mode, which might not be as smooth as a conventional auto, but there is no penalty in fuel consumption and carbon dioxide emissions.

Citroen currently only offers Sensodrive in its top C3 model, the 1.6 Exclusive. With 110bhp it means sprightly performance, although some way off a racing car. At £12,400 on the road there is a reasonable amount of standard equipment for the money.

Styling is one of the C3's strong points, both inside and out, although its tall shape and compact dimensions allow excellent headroom, while legroom in the rear can be tight.

The difficulty with systems such as SensoDrive is ensuring upchanges are as smooth as possible. Although there is no clutch pedal, there is still a clutch controlled by electronics which facilitates gearchanges. The C3 SensoDrive slurs shifts up through the transmission as much as it can, but it's always best to anticipate them and ease back on the throttle momentarily.

Model: Citroen C3 1.6 Exclusive SensoDrive
Engine (cc): 1,587
Max power (bhp/rpm): 110/5,750
Max torque (lb-ft/rpm): 108/4,000
Max speed (mph): 119
0-62mph (sec): 11.9
Fuel consumption (mpg): 45.6
CO2 emissions (g/km): 148
On sale: now Price (OTR): £12,500

Saab 9-3 Aero

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SAAB likes to draw on its heritage in the aerospace industry and for some time the high-performance variants of both the 9-3 and 9-5 have been labelled Aero.

Despite its age, the latest 9-5 Aero can teach its main rivals a few things about company car tax – no other 250bhp car offers such low carbon dioxide emissions. And earlier this year it was the turn of the new 9-3 to be given the Aero treatment. With a high-output turbo, the 2.0-litre engine produces 207bhp, more than BMW's 2.5-litre six-cylinder engine, although the Valvetronic engine in the Beemer means the 325i is slightly better than the 9-3 on CO2 emissions.

Torque is even more impressive at 221lb-ft.

The latest 9-3 is a more dynamic looking vehicle than its predecessor and as well as the improvements of building the car on an up-to-date platform, the Aero also comes with a 'sports chassis'.

Another flying analogy can be drawn with the way the Aero performs. It is no slouch and makes swift and near silent progress. Despite having four-cylinders where most rival cars offering this kind of power have six, the 9-3 is remarkably refined, even when accelerating hard. Driving Millbrook's challenging hill circuit in the wet, the Aero proved to be an able companion, with sweet steering and virtually roll-free road holding.

However, some of the banked bends seemed to confuse its stability control. In one tight bend, the outside front wheel was braked three times, despite the tyres gripping well all around the corner.

Model: Saab 9-3 Aero
Engine (cc): 1,988
Max power (bhp/rpm): 207/5,500
Max torque (lb-ft/rpm): 221/2,500
Max speed (mph): 143
0-62mph (sec): 7.5
Fuel consumption (mpg): 31.4
CO2 emissions (g/km): 218
On sale: now
Price (OTR) £22,900