| First Drive | Wiltshire, England | Subaru Impreza Cosworth STI CS400 |

The most extreme production Subaru Impreza ever is in showrooms now, armed with blistering performance, mean looks and the loudest turbocharger known to man.

In the Metal

Subaru has put its hands up and admitted that the existing five-door Impreza hasn't gone down as well as it had hoped with fans of the old four-door models (which is why it built a new saloon). The Japanese firm is keen to claw back some support from Impreza nuts with the Cossie, though.

It's a burly looking thing, with jutting arches and bumpers, quad tailpipes and the traditionally large air scoop on the bonnet. The multi-spoke, 18-inch alloys mask huge disc brakes (335mm front with six-pot callipers and 316mm rear), but the wheels themselves appear a little lost in the sculpture of the arches. It would look better wearing 19s, or 20s, but there's always the ride to consider. The Cosworth still has some way to go to match the mythical road presence of former hallowed Imprezas like the P1, the RB5 and the 22B, but that sort of status comes with maturity.

What you get for your Money

Brace yourself because the asking price is high. You'll need to part with £49,995, which is an awful lot of money for an Impreza. The cost of extracting 395bhp from a 2.5-litre flat-four engine can't be cheap, especially if Cosworth is the company behind it, but you'd need to be a serious Subaru fan to spend that much on this kind of car, especially today.

But there is some method to the madness. Mitsubishi's Evo FQ-400 retailed at £50,799 and was a tenth of a second slower to 62mph. Then there was the not quite so quick but equally crazy Ford Focus RS500, which admittedly, was about £15,000 cheaper, but £35,000 is still a heck of a lot of money for a Focus. Either way, all RS500s destined for the UK sold within a week, so there is a marketing case for this kind of car. As for fuel economy and emissions, the official line on the technical specification sheet is: "tbc".

Driving it

The first thing you notice about the Subaru is how heavy the clutch pedal is. Four-wheel drive vehicles usually require a tough clutch, but factor in 400lb.ft of torque and you need some serious ceramics to cope. For the kind of B-road driving that our road test consisted of, it was great - it felt authentic and mechanical - but in traffic it would drive you mad.

We were expecting the Cossie to be quick, but a number of expletives could be heard in the cabin during the first burst of acceleration. It is mind-bogglingly fast and the rev counter's needle seems to instantly be batting against the red line in the first three gears. A flashing red light reminds you to change gear, but moving your hand down to the stick in time is difficult. The drama is intensified by a deafening hiss from the turbocharger - easily the loudest in a production car - and an equally piercing whoosh whenever you lift of the throttle. The 0-62mph time of 3.7 seconds certainly seems accurate and it's (very) limited to 155mph flat-out.

The steering is surprisingly delicate for such an extreme thing. It seems lighter than that of the standard Impreza STI and, though not brimming with feedback, it isn't bad, and certainly makes the car easy to place on the road. The ride is a little bumpy, but fairly composed and the chassis communicates well and grip is plentiful. However, you need to watch your right foot. There's so much grunt available that's it's easy to steer the car on the throttle and indulge in a little power oversteer out of corners, which isn't typical of a four-wheel drive car.

Worth Noting

It's a sad thought, but the Cosworth STI could be something of a last hurrah for hardcore Imprezas. It's no secret that high running costs and a waning interest in rallying have moved the Impreza out of the public eye and Subaru is gradually changing its customer focus to more sedate cars like the Outback and Forester, which are now its two best-selling models. The firm also described the standard, non-STI Impreza as "a disappointing car for us" as it simply hasn't taken off in the UK.

There is hope on the horizon though, in the form of a new coupé. The model is a joint venture with Toyota and is likely to be sold as both a Subaru and a Toyota. In a break from tradition, it will be rear-wheel drive and have 200bhp. Expect to see it in mid 2012.

Summary

There's no denying that £50,000 is a hell of a lot for an Impreza, but it's a hell of a car. Only the most serious of supercars or very special Caterhams will outpace it on the road and the engine is truly awesome.

The difficult-to-justify bit comes when you open the door and see the same low-grade plastics as you'd find in the standard car. That said, it's still quite practical for such a fast car and the Cosworth emblems on the seats and the dash help to take the sting out of things. If you like your Imprezas, then you'll certainly like this.