NISSAN Australia this week introduced the annual upgrade of its iconic GT-R supercar, with significant improvements in performance, handling and efficiency, in return for a modest $2000 price increase to $170,800.

As well as getting a significant boost in power and torque, the 2012 model year GT-R features what Nissan claims is a world-first with asymmetric suspension settings to optimise handling in right-hand-drive models.

Nissan claims the 1740kg four-wheel-drive GT-R now accelerates from 0-100km/h in a blistering 2.8 seconds.

Globally, Nissan has sold some 20,000 of the R35 series coupes – the fourth generation of the famed GT-R line – since it was launched in December 2007, including 420 in Australia in the three years is has been sold here – two-thirds of them in the first year.

Power output from the 3.8-litre twin-turbocharged six-cylinder engine has been boosted by 14kW (up to 404kW at 6400rpm) while torque lifts 16Nm (to 628Nm between 3200 and 5800rpm) compared with the previous iteration, which itself was launched here only 12 months ago.

The latest figures are much higher than the 357kW and 588Nm claimed for the car when it was launched here in early 2009.

Each engine is still hand-built by one of eight engine assemblers at the factory in Japan, but with improvements to exhaust and inlet efficiency, with tighter cam and head clearances, more precise matching of the ports of the intake manifold to the cylinder head and replacement of the aluminium intake duct with one made of plastic.

New sodium-filled exhaust valves are fitted – for the first time in a Nissan since the 200SX was discontinued nine years ago – to improve cooling and suppress ‘knocking’.

By improving the internal efficiency of the engine, the Nissan engineers have been able to install a more compact and lighter catalytic converter under the floor, which has further improved exhaust efficiency.

Turbo boost has not been increased, so the performance increase is entirely the result of mechanical refinements.

Nissan claims the resultant torque curve is flatter, and at higher revs, resulting in an even more muscular feel on the road than the bare numbers suggest.

As well as releasing more performance from the twin-turbo V6, the latest refinements have considerably improved fuel economy, dropping the official combined figure from 12.0L/100km last year (and 12.4L/100km in 2009) to 11.7L/100km, with concomitant improvements to emissions.

Shift feel and quietness from the rear-mounted six-speed dual-clutch transmission are claimed to have been improved through internal refinements while the built-in diff now uses a race-spec oil.

Nissan has introduced the asymmetric suspension settings in right-hand-drive models to account for the extra weight of the driver in addition to the fact that prop-shaft that takes drive to the front wheels also runs down the right-hand side of the vehicle.

In left-hand-drive GT-Rs, the weight of the prop-shaft on the right is balanced by the driver on the left.

Consequently, RHD models for markets such as Japan, the UK and Australia now have stiffer right-hand front springs while the left-hand rear suspension arm is 25mm higher than the right to alter the wheel load.

Nissan claims that this results in an equal balance of the vertical load on all four tyres whereas previously there was a 50kg weight bias to the right on Australian cars with an average-size driver.

In terms of standard equipment, the MY2012 GT-R gets a rear-view camera and upgraded Bose woofers, as well as solid aluminium diecast mountings for the centre-rear woofer and door speakers to reduce vibration.

Structural reinforcement around the rear part of the engine compartment and dash panel, along with relocation of some control sensors, are claimed to deliver more responsive handling and feedback to the driver.

New Dunlop SP Sport Maxx tyres are fitted – 255/40 front and 285/35 rear – but still mounted to 20-inch alloy wheels (9.5-inch wide at the front and 10.5-inch at the rear).

Externally, the latest GT-R looks exactly the same as last year’s model.