The launch, two months ago, of the revised cee'd was an important one for Kia, but perhaps no single model was as significant as the EcoDynamics hatchback. EcoDynamics is Kia's buzzword standing for something like, "Look! Low-CO2 model! The dolphins are safe with us," (and therefore equivalent to other manufacturers' BlueEfficiency, BlueMotion, Ecomotive, ECOnetic, and all that jazz), and although it is also applied to the three-door pro_cee'd and SW estate versions, it's going to find a wider audience with the more straightforward five-door tested here.The EcoDynamics is based on the mid-range cee'd 2 (Kia, like Skoda, has a rather austere way of naming its trim levels these days), and several of the features which contribute to its unusually high fuel economy and low CO2 emissions are already found on other models in the line-up: the less powerful - 89bhp rather than 113bhp - of the two 1.6-litre CRDi turbo diesel engines is not unique, for example; nor is its higher gearing in fifth and sixth, because all the 89bhp cars have that, and nor is the fact that it runs on low rolling resistance Michelin Energy Saver tyres.What is special is that the EcoDynamics uses Kia's new Intelligent Stop/Go system, which follows increasingly common practice by switching off the engine when the car comes to rest (assuming there is enough juice in the battery for this to be prudent) and firing it up again when the driver presses the clutch. The system really comes into its own in town driving, so it makes sense that the EcoDynamics model is by far the most economical cee'd on the urban part of the EU cycle.It also the least thirsty and CO2-ish version overall, but by a much smaller margin. 67.3mpg combined and 110g/km are good figures, but they are not dramatically superior to those of the regular (and rather faster but identically priced) cee'd 2 1.6 CRDi, and the gap to the similarly-powered but considerably cheaper cee'd 1 with the same engine is smaller still.At present, all three cars cost the same to tax, and when the new VED system comes into force in April 2010 the advantage held the EcoDynamics will be just £10. This, along with the fact that similarly-sized cars officially emitting less than 100g/km of CO2 - and therefore completely exempt from VED - means that the EcoDynamics is not unduly impressive as a low-CO2 car, though the improved fuel economy should eventually make a difference if you keep driving for long enough.One final point about ISG is that, despite the use of the word "intelligent" in the name, Kia has admitted that the system isn't as sophisticated as others on the market. At first it's difficult to find a symptom of this, but I eventually did when I realised that, as the engine restarts, the radio switches off, and then comes back on about five seconds later at its default volume setting, which may not be the one you had previously chosen. Slightly irritating, but no more than that. The real confusion came when occasionally the radio didn't switch off at all. I still haven't worked out why this should be.There endeth the discussion about ISG. In other ways the EcoDynamics, like all revised cee'ds, is rather a charming car to live with, and certainly a good deal better than the older models. I've finally decided that I like the mild restyling job, though I wasn't entirely sure to begin with, and there is no question that the driving process has been improved beyond all hopes.All versions of the original cee'd handled well, at least on smooth roads, but the ride was distinctly sub-standard. Kia's efforts to resolve this for cars sold in the UK has paid off tremendously, and although there are still some minor issues (the suspension doesn't carry the weight of the diesel engine as effectively as it might, and you need to be very smooth to avoid a slight lurch as you turn into a corner or straighten up afterwards), the behaviour is in general as good as it needs to be for a car of this type.I've also become quite fond of the 89bhp engine. I'd better lay my cards on the table here: I know now, and must have known before, that the EcoDynamics used the less powerful 1.6 diesel, but when I was driving the car that little fact completely slipped my mind. I wasn't reminded of it by any lack of useful performance, so I have to conclude that 89bhp is as much as the cee'd really requires.The interior is also smarter than it was before, though I find the placing of the trip computer button on one of the two south-facing spokes of the steering rather inconvenient. And since the new cee'd has exactly the same basic bodyshell and therefore window arrangement as the old, the visibility - especially at the rear - is still ridiculously bad. Yes, regular readers (especially the ones who work for Kia) are probably fed up of me saying this, but I won't stop until something has been done about it. Engine 1582 cc, 4 cylinders Power 89 bhp @4000 rpm Torque 173 ib/ft @1750 rpm Transmission 6 speed manual Fuel/CO2 67.3 mpg / 110 g/km Acceleration 0-62mph: 13.5sec Top speed 107 mph Price From £14951.00 approx Release date 01/10/2009