They may be at opposite ends of the luxury spectrum, yet there is one feature about the Lexus GS Hybrid which makes it strikingly similar to the Rolls-Royce Phantom - neither car has a conventional tachometer.

Instead of engine speed, the Rolls-Royce has a "power reserve" meter to indicate how much power is available. In the Lexus, a Hybrid Meter shows the level of electrical output in kilowatts.

This particular Lexus is a petrol- electric hybrid version of the familiar GS300 sport sedan, after all. Called the GS450h, it has a 3.5-litre V6 direct injection petrol engine hooked up to two electric motors. One of the motors generates electricity for storage in the high voltage battery while the other complements the engine by driving the rear wheels. As a result, this hybrid powertrain boosts the engine's maximum output of 292 hp to a combined 339 hp.

On the road, this translates to scintillating performance. Floor the accelerator and the GS450h's prodigious 368 Newton-metres of torque provide an oomph that you are unlikely to experience in the GS300. The latter has a 3.0-litre V6 engine and it has good power but the GS450h is, well, electric.

The car flies. And smoothly and silently too. It is the fastest Lexus ever, accelerating from zero to 100 kmh in under six seconds. Rear-wheel-drive also means it can also be driven sportily, aided by the adaptive variable suspension which can provide for a stiffer ride and more precise steering if so required. Unlike the flagship Lexus LS600h L, the Japanese luxury carmaker did not make the GS Hybrid four-wheel-drive because it wanted to avoid a weight increase and to maintain the GS's sporty character.

At the same time, the GS450h is relatively green. Its Lexus Hybrid Drive system may focus on outright performance but it does not throw fuel economy out the window. The GS450h may perform like it has a 4.5-litre V8 engine but it turns in the mileage and low emission of a 2.0-litre V6 (Lexus says the combined cycle mileage is an eyebrow- raising 12.6 km per litre).

In fact, the system is so good that the GS450h can operate in full electric mode for up to 40 km if it is driven at a constant speed of 40-50 kmh and with the aircon off.

For the GS450h, Lexus has also introduced a new feature - Variable Gear Ratio Steering or VGRS. This electric system controls the turning angle of the front wheels according to the vehicle's speed. At low speeds, less steering effort is needed, and at high speeds, the vehicle response is milder. But while it works, the steering is too dull for something that is supposed to be a performance sedan. The driving position is also not ideal for anyone six feet or taller.

But as a luxury hybrid sedan, the GS450h blends the best of both worlds - power and economy. It possesses the qualities that are now expected of every Lexus - the quiet cabin, luxury fittings and excellent ride comfort - plus the additional cachet of environmental consciousness. What an electric combination.

This article was first published in The Business Times on Dec 13, 2008 .