And it's not just the fore-end that has been facelifted. The rear has been tidied up, too, with new tail-lights that mimic those at the front, 'enhancing overall design integration', as Subaru puts it. The rear spoiler is even bigger on the latest STi. Combined with new spoilers at the front corners and reshaped sills, it's said to improve high-speed stability. It also makes the little car look even more like a caricature of its muscular self.

There's very little different under the more palatable exterior, but what there is has a positive effect. There are uprated bushes on the tops of the front suspension struts, a new cross-bracing strut between the turrets and more new bushes on the lower linkages. This all adds up to a reduction in geometry change under hard cornering and hence better control.

Outputs are unchanged - the Type UK version will still have 261bhp at 6000rpm and 253lb ft at 4000rpm - but performance is claimed to be marginally improved thanks to a much bigger bonnet scoop with revised baffling that feeds cooling air to the massive intercooler nestling beneath. There is also a change in the shape of the intercooler water-spray nozzle.

Inside there is new trim, a revised centre console, different instruments, whiplash-reducing 'active' head restraints, and a new energy-absorbing brake pedal. The most obvious change for the driver, though, is a smaller, 375mm diameter, Momo steering wheel. It's still too big, but much better than before.

The good news is that the Scooby drives even better than before, too. The marginally tauter suspension makes its presence felt and is a deal crisper than the outgoing model's. The Scooby has always been less racecar-like than its arch rival the Mitsubishi Evo, but the '03 STi narrows the gap fractionally and is now nicely more throttle sensitive. When turning-in, the car can be balanced more easily with the throttle, to the point where you can loosen the rear end quite readily by easing off in tighter bends.

That's it, then: the WRX STi is a sharper-handling package in a much nattier suit. But also of interest at the STi launch, in the hills around Mount Fuji, was the revised Japanese-spec car. Why? Because some of the changes might find their way onto UK cars at the next round of revisions, and one in particular affects the very character of the car.

The Japanese-spec engine is gutsier - 276bhp at 6000rpm, a stunning 290lb ft at 4400rpm and an 8000rpm rev range - and a whole lot more responsive than previously. How so?

Subaru Tecnica International (STi) has revamped the boxer engine for Japan with a new nitrided crankshaft and con-rods and revised pistons. There's also a new exhaust system and turbo that supplier IHI calls its 'twin scroll' unit.

IHI advised Subaru that the odd-phased exhaust cycle of the flat-four engine was causing interference as the exhaust gases entered the turbine, harming efficiency. To cure this, IHI came up with a siamesed exhaust running into twin chambers in the turbo housing, resulting in a much faster spin-up speed and thus less turbo lag.

The results are stunning, most especially in the lightweight 'Spec C' STi model, which features an extra revision to the turbo, namely a more efficient (and noisier) rotor bearing that further enhances throttle response. All this in a chassis with WRC-inspired mods, such as revised front suspension castor for even niftier steering, more rigid mounting of the suspension to the subframe and retuned rear geometry.

On twisty and often bumpy switchback roads it was a revelation, with huge grip to go with the punchier performance. The smaller steering wheel helps make the car feel more agile but there's no doubt the basic chassis mods pay huge dividends, even if it's still not quite as rewardingly cohesive as the Evo VII.

But there's a downside. That exhaust-pulse interference eradicated by IHI is what gives the Scooby its distinctive growling exhaust note. You still get the boxer grumble through the seat of your pants but no longer hear it. There are no plans yet to fit the revised turbo to UK-spec cars, but if Subaru does, will buyers feel that the extra response is worth the loss of that fabled Scooby growl?