SUBARU Australia’s halo WRX and STi models have gained the lion’s share of improvements to the MY06 Impreza range, with both now featuring 2.5-litre turbocharged engines and the marque’s controversial new corporate face.

The niche Japanese brand has also dropped the 2.5-litre RS model in favour of a variant called the 2.0R, which features a 2.0-litre DOHC engine with Subaru’s Active Valve Control System.

The line-up now comprises 2.0i sedan and hatchback, RV hatch, 2.0R sedan and hatch, WRX sedan and hatch and the STi sedan.

The STi produces 206kW at 5600 rpm – up from 195kW – while torque is up 14 per cent from 343Nm to 392Nm at 4000 rpm.

Subaru claims the STi’s power and torque delivery has improved right across the engine operating range.

In the WRX, power is up marginally to 169kW at 5600rpm, while torque is up 6.6 per cent to 320Nm at 3600rpm. The WRX is now only available as a five-speed manual while the six-speed unit in the STi carries over.

Gear ratios remain the same but Subaru claims the engine improvements offer a better spread of torque and in-gear acceleration.

The 2.0R unit offers a wider torque band, producing 118kW at 6400rpm and 186Nm of torque at 3200rpm compared to the RS’s 112kW at 5600rpm and 223Nm at 3600rpm.

Prices have risen in some cases. The starting price for the WRX has increased $1000 to $40,990, although in addition to the engine the model features high-intensity discharge headlights, a larger-diameter exhaust and new alloy wheels.

STi pricing has also increased, up $360 to start from $56,990 on the back of a raft of technical changes.

Impreza 2.0i remains the same as superseded GX at $23,990, while the $29,990 2.0R matches the previous RS model and the RV remains at a $26,940 price point.

Standard features across the range include all-wheel drive, climate-control air conditioning, anti-lock brakes with electronic brake-force distribution, aluminium bonnet, four-speaker CD stereo, cruise control, microdot vehicle identification, dual-range transmission (manual hatch), foglights, four-wheel disc brakes, height adjustable driver’s seat, immobiliser, electric windows/mirrors and remote central locking.

All Imprezas except the STi introduce side airbags for the first time, supplementing the dual front airbags.

Visually, the entire range adopts the latest Subaru design philosophy penned by head designer Andreas Zapatinas, which means a controversial, aviation-inspired three-part mesh grille.

The bonnet is extended, with more efficient air inlets used on the high-performance models. For added aerodynamic performance, the STi adds an aluminium roof vane. A rear under-body diffuser also improves the coefficient of lift by 0.03.

There are new five-spoke 16-inch alloys on the 2.0R and seven-spoke 17-inch alloys on the WRX. All models bar STi – which has unique fog-light covers – gain a re-profiled front bumper incorporating new compact fog-lights.

The WRX and STi now have smaller, more aerodynamically efficient letterbox bonnet scoops while the driver control centre differential (DCCD) on the STi has been further refined.

The torque-sensitive gear-type LSD operates ahead of the electromagnetic clutch, allowing more linear and responsive torque distribution to front and rear wheels as required, for improved stability. Subaru claims this helps maintain agility, steering stability, traction and control, particularly when cornering.

The WRX’s gearshift mechanism has also been refined while the 2.0R, WRX and STi now have "drive-by-wire" electronic throttle control.

The STi’s gearshift improvements offer smoother and more direct changing by virtue of carbon on fourth, fifth and sixth gear synchroniser rings. First and third gear synchronisers are now double-coned in all five-speed manual Imprezas, producing a lighter shift feel.