The exterior styling touches, which give only subtle hints that this is any different from one of the more standard cars in the line-up, come nowhere near suggesting the potency of the most sporty Vectra. The bonnet conceals the largest engine ever fitted to any car of this name, a 3.2-litre version of the renowned Ellesmere Port V6.But that engine is pretty subtle too. In this application it's whisperingly quiet, and thanks to a long-travel throttle pedal you can spend a day pottering around the countryside without feeling that the car is straining at the leash.Even for a car as bulky as a present-day Vectra, its power output of over 200bhp is more than sufficient. At the same time, you get a very wide spread of power; floor the throttle at 2000rpm and the car fairly shifts, the engine remaining smooth yet purposeful all the way to the revlimiter. Not that you're likely to feel the electronically induced stutter very often. The GSi can very nearly break the motorway speed limit in second gear, so you're unlikely to run out of revs unless you're on a race circuit or a disused runway.Whether you'd actually use this as a track car is another matter entirely. Vauxhall has geared up the steering, reduced ride height, fitted 215/50x17 tyres and fiddled with spring and damper rates to make the Vectra's chassis considerably perkier than normal, but there's a limit to what you can do with this basic material. Ordinary Vectras are large, heavy cars designed to be smooth and comfortable on long cruises. They are indeed very good at that, but if you want to make a sports car out of one you've got a job on your hands.Considering its size, the GSi makes a good job of tight country roads, but it's not at its happiest on them. It turns in well, but the clever steering system leaves you feeling remote from the front wheels and means that you feel the turn-in through the body of the car rather than through the steering wheel. Although you don't have to put in a lot of effort yourself, you can feel that a lot of weight is having to be persuaded to change direction, a process that feels slightly clumsy since the suspension, despite all the tweaks, is still biased towards ride comfort than ultimate handling.When the roads are wider and smoother, and the corners more gentle, the car really comes into its own, flowing nicely through the bends and, when required, surging between them. It's effective and effortless, and it makes this Vectra more of a Grand Tourer than other, earlier Vauxhalls (Cavaliers and Carltons spring to mind) that have had GSi added to their names.Restrained use of chrome inside the car adds a slightly up-market feel to the interior, while the sports seats are fine for the job, giving support and comfort. The only jarring feature is the speedometer, which marks out mph up to 170 in fives and km/h up to 270 in tens. The top end, with all those lines and three-figure numbers, is pretty crowded, and not in character with the more minimalist dials elsewhere.In addition to the considerable amount of equipment standard to all Vectras, and the extras used on the SRi models, the GSi gets those seats, a CD multi-changer, electronic climate control, electric rear windows, xenon headlamps and its own design of alloy wheel. Avid GSi-watchers will note that while the sports bumpers and rear spoiler are the same as on the SRi, this car gets twin oval tailpipes rather than the single oval of the SRi.Vauxhall people were irritated recently when a print magazine put a GSi up against a high-performance Ford Mondeo in a track test and concluded that the Vectra was far softer and less effective in those conditions. "We could have told them that ourselves," a spokesman muttered. Indeed so - this isn't a road racer, but a car that tries to combine sportiness and everyday usability, and does a pretty good job of it. Engine 3175cc, 6 cylinders Power 208bhp Fuel/CO2 28.0mpg / 243g/km Acceleration 0-60mph: 7.0 seconds Top speed 155mph Price £20,980 Details correct at publication date