Subaru's Model Year 2005 Impreza range is bolstered by the addition of a sporty 2.5 litre RS hatch and multiple enhancements to the rally-bred WRX STi, taking its All-Wheel Drive abilities to a new level.

The ever-popular Impreza WRX now also has inverted suspension struts, producing even better stability.

New, wider eight-spoke wheels are the most visible of a raft of changes on turbocharged Impreza WRX STi.

For the first time it features a driver control centre differential (DCCD) - allowing the driver to literally "dial up" the preferred torque split, when in manual mode, or opt for automatic mode. A new front helical limited slip differential is added too.

Steering response on Impreza WRX and STi also benefits from the new "cannon mount" steering rack housing.

Combined, these features enhance steering feel and improve vehicle control, especially on slippery surfaces.

Pricing on the vast majority of MY05 Imprezas remains unchanged - but has declined by $1,000 on RS sedan variants and $1,050 on RV models, while factory-fitted air conditioning is now standard in entry-level GX at existing prices. Although this model will not be available until late September, dealers are taking orders now.

A $2,000 insurance rebate is included as part of Impreza WRX recommended retail pricing.

STi's legendary handling is further improved by stretching rear tread 10mm to 1495mm and wheelbase by 15mm to 2540mm. Caster angle is also increased by 1.25 degrees. Together, these improve stability, handling and vehicle footprint.

Aiding aerodynamic performance and under body protection, an underfloor cover is added.

Rear bumper and rear wheel arch flares are redesigned to incorporate the new distinctive alloy wheel design.

Inside, new seat side material provides even better occupant support.

Nick Senior, General Manager, Subaru Australia, said: "We are adding value across the Impreza range, yet have managed to maintain and in some cases reduce pricing.

"There's also the bonus of factory-fitted air conditioning as standard on entry-level Impreza GX.

"The addition of a 2.5 litre Impreza RS hatch broadens the appeal of the range and with our icon STi adding even more rally-honed technology, we are confident of even more success for Impreza."

Impreza WRX STi engineering changes

The DCCD allows the driver to control torque distribution - once a position is manually selected, the automatic All-Wheel Drive function is over-ridden and torque split is dictated by the driver.

The DCCD can be adjusted from 50:50 up to a maximum of 35:65 torque split (front:rear).

When in automatic mode, the DCCD uses input from a yaw rate sensor that ensures optimum torque split when cornering.

A new front helical limited slip differential is added too.

Together, these features enhance steering feel and improve vehicle control, especially on slippery surfaces.

To reduce kickback through the steering column, damper valves are added to the STi.

The rear differential cushion spring rate is increased, improving handling stability.

The STi's front suspension bracket housing is strengthened to enhance strut firmness and accommodate the wider 8JJ eight-inch wide wheels.

Front and rear suspension links are now aluminium.

Steering firmness is improved in both Impreza WRX and STi, with introduction of a "cannon mount" steering rack housing.

Increased diameter front and rear sway bars are added and, in addition to the refined suspension geometry, this produces more stable cornering, while maintaining high speed stability.

A unique wheel mounting and bearing design produces optimum strength and stability between axle and wheel, raising the cornering threshold.

Impreza WRX

Inverted suspension is introduced, producing improved suspension stability, while the use of aluminium in some suspension components reduces the unsprung weight.

The five-speed manual transmission features a double synchronizer cone on first gear, improving shift quality.

Impreza RS

For the first time, the 2.5 litre Impreza RS is available as both an automatic and manual hatch.

Other MY05 Impreza refinement:

Interior

A new aluminium-look centre console design enhances cabin ergonomics, including air conditioning control.

The front cup holder is relocated next to the hand brake lever. All Imprezas other than dual range variants now have two front cup holders.

Three-spoke steering wheels are now a feature of all Imprezas, while the diameter is reduced for all naturally aspirated and WRX variants.

On the windscreen, ceramic dots are added in the top centre, reducing sun glare in the gap between visors.

Engineering

Brake hoses are changed to a lower expansion design, producing a firmer feel. Brake booster thickness is also increased for better brake feeling.

All MY05 Imprezas get compact ABS 8-type, reducing weight, while retaining the Australian-tested calibration to suit local conditions.

Impreza MY05 pricing