Lexus introduced its first turbocharged engine here last year, in the NX200t.

The dual-cycle 2-litre four-cylinder forced-induction engine has since been rolled out to the RX, IS and now, the GS. But it is in the GS that it really shines.

The GS is Lexus' mid-sized premium performance sedan, which goes head to head with BMW's 5-series. So it has to offer power as well as refinement.

Can a 2-litre four-pot unit do the job? After just five minutes in the facelifted sedan, the answer is clear - the engine is not only up to par, but it is also indistinguishable from the GS V6's.

It is super punchy, especially in the low and mid rev ranges. From just 1,650rpm, you get 350Nm of torque. The 3.5-litre V6 variant produces 380Nm from 4,800rpm.

Although the GS200t's peak power of 241bhp (at 5,800rpm) is shy of the GS350's 310bhp (at 6,600rpm), most driving duties in Singapore are accomplished between 1,500rpm and 3,500rpm.

In this range, the GS200t feels punchier than the GS350, even if its century sprint of 7.3 seconds is less impressive than the GS350's six seconds.

But wait. The new engine does not replace the GS350's naturally aspirated 3.5-litre V6. It replaces the GS250's 2.5-litre V6. The latter produced 209bhp and 253Nm and propelled the GS to 100kmh in 8.6 seconds.

If the GS200t's output is dramatic, the car's refinement is equally remarkable. Hopping into the car without being told what it is, you would never guess its engine type.

Because Lexus is renowned for its quiet and vibration-free operation, any slight degradation would be noticeable. The fact that you do not notice any difference says a lot.

Carmakers from BMW to Mercedes-Benz to Ford have likewise done amazingly well with downsizing. But it appears that Lexus has taken it half a notch higher with the GS200t. Either that, or the Toyota-owned brand has perfected the science of insulation.

Some credit must also go to the car's new eight-speed autobox, which is seamless, satiny and affords lower revs and better efficiency on highways.

The GS is now a keener rival to the 5-series because of its revised drivetrain. Its firm suspension sharpens handling somewhat too. But I prefer the old setting, which was more in line with Lexus' values.

If I wanted something that performed like a 5-series, I would get a 5-series.

Meanwhile, the facelift has given the GS sharper and fancier lines, especially in front, where a new, flashy 3D grille glowers .

Changes have also been made to the lights, front and back. The car's side skirts are also more prominent now.

The changes are effective, giving the previously subdued-looking sedan a more modern and confident stance.

Combined with the new drivetrain, this nip and tuck makes the GS a very enticing luxury performance machine. That it now attracts less road tax does not hurt either.