By JAMES STANFORD

SUBARU has overhauled its turbo Impreza range in a bid to boost sales by about 30 per cent.

It has taken a punt by bringing WRX and the WRX STI closer while making them both more easily differentiated from the non-turbo Imprezas.

The wide body of the previous STI hatch is now being shared with the cheaper WRX, while a new wide-body sedan has been introduced as both a WRX and an STI.

Subaru Australia managing director Nick Senior denied the company risked diluting the STI brand with the styling similarities.

“What we are trying to do is harness the power of two iconic brands, one WRX and one WRX STI,” he said.

“They have the same identity, different DNA to create a performance channel.”

Mr Senior added that the STI brand was sufficiently strong for enthusiasts to spot the STI badge and realise that is was different to a regular WRX.

Even so, Subaru has given the STI sedan a boy-racer design cue after trying to distance itself from this group with the previous model, by fitting the STI sedan with what it describes as a ‘massive’ boot-mounted spoiler. The WRX sedan gets a more sedate boot-lid spoiler.

Subaru Australia says it expects strong demand for the sedan version of the STI, which has been missing since the new model was introduced in 2008, and tips that it will account for about 70 per cent of STI sales.

In another boost for STI sales, Subaru Australia is finally introducing an optional automatic transmission, which has been available in Japan, for the first time.

Subaru Australia tips that 70 per cent of STI customers will choose the automatic, which is a regular five-speed torque-converter transmission instead of the more advanced dual-clutch automatic available in the STI’s arch rival, the Mitsubishi Lancer EVO.

The improvements for both the WRX and STI will not cost extra, with Subaru keeping the price for the entry level WRX pegged at $39,990 – the same price as at its initial launch in Australia in 1994.

In the case of the STI, Subaru has hacked $2000 off the price, which now stands at $59,990.

Engines are unchanged except in the case of the STI which a revised torque map.

Both the WRX and STI run a 2.5-litre turbocharged four-cylinder boxer engine with a top-mounted intercooler, but the WRX has variable valve timing only on intake camshafts.

The WRX’s peak power is 195kW at 6000rpm and 343Nm at 4000rpm. It is available only with a dated five-speed manual transmission that affects fuel consumption at highway speeds.

Subaru Australia says it is important to maintain a point of difference between the WRX and the STI which is available with a six-speed manual.

The STI’s engine runs variable valve timing on intake and exhaust valve, a different compression ratio and more boost. Power output stands at 221kW at 6200rpm for both the manual and automatic versions.

The engine generates 407Nm of torque at 4000rpm, while the automatic generates 57Nm less torque, but can do so through a wider range from 3000rpm through to 6000rpm.

There are some other changes for the automatic STI which has a mechanical centre differential that runs a torque split of 45 per cent front and 55 per cent rear. It also runs an open-front differential and a viscous rear limited slip differential (LSD).

The manual STI uses an electronically controlled centre differential, the ultra complex Driver Controlled Centre Differential, as well as a helical front LSD and a Torsen rear LSD.

Drivers can change gear themselves with the automatic transmission by using the regular shifter or by operating the rally-inspired paddles behind the steering wheel.

Subaru has also taken the opportunity to improve the suspension set-up of the STI after testing spring and damper rates in Australian conditions.

The suspension is 5mm lower, the spring rate has been increased, the damping has been revised and there are thicker front and rear stabiliser bars.

Subaru has also added new aluminium lower arms to the front suspension, while the rear suspension subframe has been revised.

The STI has new Enkei 18-inch rims as standard, with are a combined 7.2kg lighter than those they replace and there are also new stainless steel exhaust tips.

There is also a darker instrument panel and door trim as well as Bluetooth and a USB jack.

The front bumper has been revised with air vents to help cool the brakes.

Pricing for the STI kicks off at $59,990 for the both the sedan and hatch and there is no price difference between the manual and automatic.

For an extra $6000, customers can upgrade to the Spec R with leather seats, even lighter BBS alloy wheels, satellite navigation and sunroof. The leather seats can also be swapped for sportier Recaro seats for another $1000.

The WRX not only scores a bold new look, thanks to the muscular new wide body, but also inherits the road-holding improvements that come with having a greater footprint. Its track is wider by 35mm at the front and 40mm at the rear, and tyre width has grown 10mm.

The WRX sits on 17-inch alloy wheels painted in gunmetal grey, while the rear suspension has revised sub-frame bushings and the front brakes have been upgraded with 16-inch callipers.

It also now gets the same four tail pipe exhaust set-up as the STI.

The sedan and hatch WRX both cost $39,990, while an upgraded model with satellite navigation, leather seats and a sunroof costs an extra $4000.

Both the WRX and STI come with a five-star ANCAP crash test rating, electronic stability control and front, side and curtain airbags. All have an alarm and DataDot tracing technology.