Subaru Impreza Cosworth STI CS400 (2010) review

Published:22 December 2010

Subaru Impreza Cosworth STI CS400 (2010) review
  • At a glance
  • 4 out of 5
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  • 3 out of 5

Two famous names in motoring meet to create this car: Subaru Impreza and Cosworth. It should be a match made in heaven, but we’re going to give the game away early. It’s not.

We declined early drives in the Subaru Impreza Cosworth STI CS400, as they were pre-production prototypes, and the first reviews were lukewarm. Or maybe that should be scorching hot (the test cars overheated). But the car they delivered to our Performance Car Of The Year 2010 challenge was a fully fettled, ready-to-go customer-spec car.

What makes the Subaru Impreza Cosworth?

Take one regular Scooby, mix in the STI spec and take it to fabled tuners Cosworth. The result is a 395bhp 4wd super-hatch that looks damn tempting on paper. As well as that badge-giveaway 400ps, you get 400lb ft and a tweaked-up chassis.

Just 75 Scooby Cosworths will be built for the UK market. The 2.5-litre boxer four has been tuned to produce 33% more power. Cosworth removes the engine from the STI, fettles the turbo, fits new pistons, forged conrods and a higher-pressure oil pump. Also tweaked are the exhaust, suspension, brakes and wheels.

Subaru says the regular six-speed manual ‘has carbon syncromesh applied to the top three ratios’ to handle the extra thrust. An upgraded single-plate clutch is fitted too, while the 4wd system retains a 50:50 split.

Suspension is upgraded with new Eibach coil springs and Bilstein dampers, dropping the ride height by 15mm at the front. Cosworth-commissioned AP brakes are fitted at the front, while the STI’s rear discs and ABS are carried over.

The road test review bit

We expect great things from the Impreza. Subaru quotes 0-62mph in a faintly ridiculous 3.7sec and truth is, it doesn’t feel anywhere near as fast. We didn’t time it, but would put the acceleration at nearer five-point-something.

Part of the problem is the mother of all turbolag. Pin the throttle and unless the engine’s spinning at around 3500rpm, nothing happens. There’s a slow build-up and then, suddenly, your ears are full of whistles and whooshes and the Cossie leaps forward like a scalded pet, the quad exhausts belching smoke. It’s all very 1980s.

The drivetrain feels agricultural, too. There’s a degree of shunt at low speeds and it’s difficult to feather the clutch to drive smoothly around town. That gearshift feels built to work on a combine harvester: it’s heavy and reluctant, with an unsatisfying action. The brakes aren’t much better, with poor feel and after a week in France, they’re juddering.

At least the Subaru Impreza Cosworth STI CS400 rides well. There’s a pillowy absorption to the way it handles bumps and lumps, and it in fact made a good autoroute companion. Therein lies the irony: the Scooby should shine on the twisty mountain roads, but it doesn’t; it’s more at home at an M-way cruise, where the monumental lag and stiff gearchange are less of a hindrance. 

It’s thirsty, too. We averaged 17mpg during our week with the car.

What about inside the Subaru Cosworth?

The interior is disappointingly boggo, which means a plasticky, but no-nonsense cabin with the tinniest-sounding doors this side of a Matchbox model. On the one hand, I approve of Subaru’s unpretentious dashboards – they’re easy to use and feel built to last. But when you spend £50k, I expect more.

The seats are too flat and left us lurching around as the Cossie was flung around the mountainous roads around Provence. The pews fitted to the regular 2011 STI are far better. 

But on the flip side, the Impreza is a practical five-door hatchback. Subaru may be returning to the four-door notchback layout, but there’s a certain Euro-spec usefulness to the existing Impreza.

One example of the patchy quality evident in the Impreza Cosworth is the alarm. Why Subaru UK persists with the shabbiest sort of aftermarket alarm system we used to see in the 1980s is anyone’s guess. It doesn’t work. We must have woken dozens of paysans in our French PCOTY adventure, the alarm going off nearly every time we unlocked the car. And yes, we did follow the correct procedure. This is no one-off. Just watch other Scooby drivers unlock their cars at the petrol station.


The Subaru Impreza Cosworth STI CS400 disappointed us. We took it along to PCOTY as a wildcard entry, based purely on its latent potential. It competed in esteemed company, and perhaps that coloured our view of it.

But far from lurking in the shadows of the Ferrari 458 Italia and Lamboexotica, the humble £24k Renaultsport Megane Cup showed us everything the Cossie wasn’t. It was a wholesome reminder that you can get twice as much fun in a hot hatchback for half the price.

Sadly, the promise of the Scooby Cossie is miles from the reality.


Price when new: £49,995
On sale in the UK: Now
Engine: 2457cc turbocharged flat four, 395bhp @ 5750rpm, 400lb ft @ 3950rpm
Transmission: Six-speed manual, four-wheel drive
Performance: 155mph, 3.7sec 0-62mph, na mpg, na CO2
Weight / material: 1505/steel
Dimensions (length/width/height in mm): 4415/1795/1475


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  • Subaru Impreza Cosworth STI CS400 (2010) review
  • Subaru Impreza Cosworth STI CS400 (2010) review
  • Subaru Impreza Cosworth STI CS400 (2010) review