Perhaps without many people really noticing, the Corsa is maintaining a very strong position in the UK sales charts, although the month when it stopped the Focus's amazing run of "wins" was rather a freak, and hasn't been repeated.The range has been tweaked for 2004, so that it now takes in Expression, Life, Active, Design, SXi and SRi models - the Life series including an ECO variant - with a selection of one-litre, 1.2, 1.4 and 1.8 petrol engines, CDTi turbo diesels of 1.3 and 1.7-litre capacities, and the familiar three- and five-door body styles.Each update of the Corsa has increased the car's appeal, although, since many of its supermini rivals are much more recent designs, it is undoubtedly showing its age. There’s no hiding the fact that against some of the direct competition it hardly looks like an up-to-date 21st-century affair, but the 2004 model has a number of styling and interior changes, and the 1.3-litre CDTi is the first Vauxhall to use the impressive little Fiat turbo diesel engine.In fact, as we've mentioned before, advanced turbo diesel technology - officially from Fiat GM Powertrain - is probably the most important thing Fiat currently brings to its alliance with General Motors.The 1.3-litre Fiat engine, now well proven in the Italian company's own cars, also makes sense in the Corsa. It can't provide anything like the same oomph as the 1.7-litre CDTi, of course, but it's worth bearing in mind that it rates for 0-60mph acceleration as fourth quickest out of the six Corsa models, being quicker off its mark than the one- and 1.2-litre petrol types.As well as that, it hammers them in mid-range performance and flexibility, thanks to its 125lb/ft of torque from 1750rpm, and is far and away the most economical of all the Corsas, with an extra urban figure not far short of 75mpg. And the CO2 rating is just above 120g/km.The other thing that's important to note is the fact that the Corsa isn't losing all that much dynamically. It still handles well, and the speed-dependent power steering has been modified to give a sharper response. With its decent mid-range torque for hillclimbing, precise turn-in to corners and ability to sweep through S-bends with ease, the 1.3 CDTi gives a very good account of itself on sporting roads. All the Corsa models apart from the entry-level Expression now come with ABS and brake assist as standard.From the outside, you can tell the 2004 car because of its altered wheelarch profiles, modified front end with chromed grille, different colour-keyed bumpers and much more businesslike headlamp array.Inside, the SXi has a leather-rimmed steering wheel with tilt adjustment, alloy-effect trim on the centre console, gearlever knob and handbrake, the usual neat digital display screen recessed into the centre of the fascia, and white-faced instruments which for me rather spoil the appearance.Vauxhall eased out a little extra rear legroom at the previous update, and this is a car which in three-door form provides more comfortable rear seat width rear than the five-door with its door pulls and so on.There's no need here to agonise about whether it might be a good idea to go for the Easytronic transmission. Fortunately, it's not available in either of the turbo diesel models.These cars do, however, indicate some of the benefits of running a diesel, not just in economy and mid-range pull, but also in the fact that while the petrol models have service intervals of two years or 20,000 miles, over the same period of time the CDTi versions are allowed to cover 30,000 miles.That's at best, of course. The display screen will start harrumphing about the desirability of a service at a lesser mileage as it "takes account of each driver's individual driving style".Second opinion: Yes, it's been around for a while, but the Corsa gets better with every update; in particular, the 2004 version is incomparably nicer and easier to drive than the earliest models. The diesel engine helps the process still further, and you don't have to worry about the feeble-looking power and performance figures - in the real world this is a nippy little car with impressive mid-range power for overtaking. The test car, being a higher-spec Corsa, gets a fancy aluminium-effect centre console, though the digital screen has inconveniently small readouts. Lesser versions look plainer, but their displays are much easier to read. David Finlay. Engine 1248cc, 4 cylinders Power 68bhp Fuel/CO2 62.8mpg / 122g/km Acceleration 0-60mph: 13.5 seconds Top speed 102mph Price £10,370 Details correct at publication date