Honda launched the S2000 as a 50th birthday present to itself at the start of the millennium. On paper, the car is a mouth-watering prospect: classic front engine, rear-wheel drive layout with 50/50 weight distribution. A fine low-slung and minimalist cockpit, covered by a powered roof, which looks good up or down. Then there is the engine: from only two litres and four cylinders, Honda has managed to extract 237 bhp without the use of turbo or super charging. The 118.5 bhp/litre figure is currently the highest for a production engine with natural aspiration. This is thanks to a 9000 rpm rev limit, yet the use of Honda's V-TEC system allows the driver to pootle around town as well. In essence, here is a Japanese alternative to the Porsche Boxster with a usefully lower price tag. I certainly looked forward to my week with the latest version of the car.

Lime green is not a colour I would normally imagine choosing for my new car. On the S2000 though it fits, and perhaps hints that this car is not necessarily for the average open-top sports car buyer. The colour certainly is eye-catching, and is offset by shiny five-spoke alloys. Indeed, the styling of the car does not seem to have aged at all. It looks very much a product of the Gran Turismo generation and only on close inspection do you start to appreciate the subtle curving of the body panels. In particular, the front wings are incredibly complex shapes, reminiscent of a stingray (the fish, not the car). The driver is greeted to a good view of the bonnet and wing edges. Taken as a whole, the car is rather like Cameron Diaz after a bodybuilding course - muscular and pretty at the same time, without being too lascivious.

Saying that, Joe Public quickly dismisses open-top cars as a bit girly. The quirky colour didn't help our test car in that respect. However, I had high hopes for the S2000, and though I expected refinement and sophistication, I also suspected that the soul of the Honda NSX would lie within this car. Lowering yourself into the leather sports seat is a good start. The driving position is nigh on perfect, and very go-kart like. The seats hold the driver in place through hard cornering and remain comfortable on the motorway. The steering wheel is a joy to hold, as is the stubby gearlever. The brake and accelerator pedal could be closer together, but that really is being picky. All of the controls are centred on the driver. It appears to be bare at first glance, but it works very well in practice. Every dial is within a few inches of the steering wheel. Even the stereo is controlled from its own panel on the driver's right. The only (minor) disadvantage with this layout is the lack of a clock. This is housed on the stereo, which is usually hidden behind the console panel (the 2004 model addresses this). I am not really a fan of digital speedometer displays, but the S2000's is the best I've used. It is wonderfully compact, and the length of the rev counter ensures that every time you extend the engine to 9000 rpm, you know about it.

Being the owner of an early VTEC-engined car, I am no stranger to the dual-personality of such engines. However, I was very surprised at how harsh the 2.0-litre engine in the S2000 was. Even at lower revs (when the high lift cam profile is not yet in use), the engine is noisy. I don't mind a 'busy' engine in a sporty car, but four cylinders rarely sound good, and in a rival for the likes of Porsche's Boxster and BMW's Z4, I would not have expected Honda to sacrifice refinement for performance. The drivetrain itself is worse again. There is a lot of vibration through the propshaft, and towards the end of our week, a whine had started from either the gearbox or the rear differential. I can only guess that this particular S2000 has had a hard life as a press car. Repeated standing starts could cause a propshaft to become unbalanced, which could in turn put extra load and vibration through the rest of the transmission. Until we drive the 2004 model, I'm afraid we will not be able to back that up. Interestingly, Honda claim to have improved the car's refinement as part of the upgrade.

Harshness issues aside, the engine is a cracker. It pulls well even from low revs, but at 5850 rpm, this 'girly' convertible turns into a racecar as the high lift camshafts come into play and you are hurtled towards 9000 rpm. At that sort of engine speed, a little noise is to be expected. It is not cultured in the same way a straight six is, but it certainly raises the hairs on the back of your neck. Changing into the next gear is a pleasant experience too. The gearchange feels a little notchy on first acquaintance, but once it is warmed up, it is a cinch to flick through the six gears at will. To drive 100%, you will want to keep the revs at about 6500 rpm, but in the real world, you could probably just pick a gear from 3rd to 6th and stay in that most of the day.

Once you get over the vibration of the driveshaft and the crashing and banging over less than perfect surfaces, the S2000 is actually quite capable of cornering. It is prone to bump steer (this will hopefully be eradicated with the 2004 changes), but in general it corners flat and has lots of grip. Even in the dry, you can slide the rear of the car, and I'm sure that big powerslides are possible, though perhaps best kept to the track. Interestingly, a colleague commented that it feels as if the S2000's chassis has been developed on a glass-smooth track, not British B-roads. I tend to agree. As much fun as it is to drive hard, it does not actually like bumps, though it manages to stay on line most of the time despite jostling its passengers about. Perhaps some of the improvements will change all that. As open-topped cars go, it feels pretty rigid, but in comparison to a coupe it is not. The mechanicals may be better suited to a car with a roof. One thing is for sure; the brakes are certainly up to the job of hard road driving. Despite smoke pouring from all four callipers on one particularly enthusiastic run, there was little or no fade apparent. The pedal feel itself is just right too.

The 2003 model is a wonderful car, but it took me the best part of a week to realise that. Most buyers will have no more than a quick test drive. In that crucial 15 minutes, they could easily decide against the S2000 due to its lack of refinement. As I handed the keys back to Honda, a press release landed in my inbox detailing a raft of changes for Honda's two-seater for the 2004 model year, some of which I mentioned above. They should go some way towards making the car easier to live with day to day, but the inherent sportiness should not be lost. Perhaps then more mainstream buyers will be tempted to be less predictable. A real driving enthusiast will certainly not be disappointed, and those of you ruled by head rather than heart will be glad to hear that the residuals of the S2000 are second only to its Porsche rival. It's just a pity that there is not a proper fixed-roof version.