Price and equipmentLEXUS has long delivered convincing pricing and equipment equations, and the GS F is no exception to that rule. Although the addition of adaptive suspension has now added $4540 to its pricetag, it remains superbly equipped for $153,540 plus on-road costs.

Quad-zone climate control air-conditioning, heated steering wheel and front and rear leather/Alcantara seats with ventilation and multi-way electric adjustment for the forward pair, an electric sunshade for the back screen, electric sunroof, colour head-up display and 12.3-inch colour screen with 17-speaker Mark Levinson sound system, all top the exhaustive standard kit list.

Although active cruise control and automatic high-beam have also been included, neither system matches that of its $159,900 Mercedes-AMG E43 rival. The GS F cannot steer itself within its lane – it can only alert when lane-wander occurs – and it cannot ‘block out’ the portion of beam affecting forward and oncoming cars like its German foe can. Rather, it only flicks the entire beam up/down.

Lexus has made only a single option available, too – semi-aniline full leather trim, fitted to our test car as a $2960 option.

InteriorThe current, fourth-generation GS has just blown the sixth birthday candle out on its cake, although the GS F does benefit from a mid-life update centred around its new, supersized centre screen. Fit and finish can only be deemed flawless, proving a fine match for the level of standard equipment.

While the front seats are superbly supportive and backed (ahem) by a terrific, low driving position and delightful steering wheel, this large sedan cannot escape its dated packaging. Rear legroom is only average, and width is affected by an intrusive transmission tunnel. Preference seems to have been given to the competitive 520-litre boot volume.

There are also some elements of the dashboard design that now feel dated, especially for the price. Some of the soft-touch plastics are basic, particularly on the doors, and the Alcantara-clad dash-top complete with fake ‘rivets’ looks as out of place as the central analogue clock.

By far the biggest issue, however, is Lexus’ infotainment system. Its computer mouse and cursor combination is flawed, particularly on the move, but the problem is compounded by sub-menu layers and functions that are blanked out at speed, apparently in the name of safety. Even a Bluetooth-connected smartphone has its contact list blanked out on the move, which would infuriate anyone. We would argue making a system more intuitive in the first place would be a safer solution.

Engine and transmissionEven a kerb weight of 1825kg cannot drag down the brilliance of Lexus’ 5.0-litre naturally aspirated V8 petrol engine. Without turbocharging, it sounds pure, revs faster and harder than most rival units, and delivers fine driver connection through the throttle without overwhelming the rear tyres.

En route to a 7500rpm cut-out, there is 530Nm of torque between 4800rpm and 5600rpm, with power of 351kW at 7100rpm. Outputs-wise, about the closest engine in a similarly sized sedan was the just-dropped $71,490 HSV Clubsport R8 Track Edition with 340kW/570Nm from a 6.2-litre V8. But that engine was nowhere near as good as this (twice-the-price) Japanese motor-maestro.

Lexus claims a 4.6-second 0-100km/h for the GS F, which matches the 295kW/520Nm twin-turbo V6-engined E43 but drops two-tenths behind a 331kW/550Nm twin-turbo V8-powered Audi S6.

When the engine is on song, it can feel faster. When it falls low in the rev range, however, it can feel sluggish. Mostly, the eight-speed automatic is a crisp-shifting and intuitively tuned partner, but it does have a major flaw.

Accelerating from really low speed it often holds second gear, refusing to shift back to first despite being able to do so in manual mode, and which forces the engine to feel flat. It is a significant calibration oddity that too often can leave the Lexus floundering around town.

Ride and handlingThere is no point delaying the answer to the prime question of whether adaptive suspension cures the woes of the old Sachs fixed dampers: it does, and then some. Despite rolling on low-profile Michelin Pilot Super Sport tyres, the GS F can now deliver compliance and control, with only a minor bias to the former in Normal mode and the latter in Sport.

Its steering initially feels soft on the centre position, but is actually fluid and surprisingly sharp. The front-end is not the most agile, but high grip enables fast initial turn-in while signalling to the driver to add throttle.

Doing so then pulls the GS F tight through the corner, where it displays fine balance.

If there is an issue, it concerns – as with the infotainment system blanking out functions – the software programming. Despite offering Normal, Sport and Sport+ driving modes, plus separate Standard, Slalom and Track settings for the torque vectoring system, there is no simple Sport button for the electronic stability control (ESC), as most rivals provide.

It either means going to Expert mode that mostly disengages the active safety system – something not recommended for public roads – or dealing with an ESC system that can sometimes needlessly trim power through the bend. The software simply needs to trust the superb chassis more often.

Safety and servicingIt features 10 airbags (including dual front, front-knee, front-side, rear-side, and full-length curtain protection), ABS, switchable electronic stability control (ESC), pre-collision warning, blind-spot monitor, lane-keep assistance, front and rear parking sensors and reverse-view camera.

ANCAP has not tested the GS F.

Lexus does not offer capped-price servicing, however the first three annual or 15,000km services are charged by the dealership at a ‘recommended’ $709.13, $696.05 and $709.13 respectively.

VerdictWith the ride quality issue solved, the Lexus GS F has been set free to become more things to more drivers. Specifically, to both traditional owners of the brand and new-found driving enthusiasts.

It is a quiet, smooth Japanese luxury sedan when cruising, yet can drop its cloak and turn into a surprisingly focused and energetic machine when pressed.

This Lexus remains imperfect in terms of cabin ergonomics, premium ambience, automatic gearbox calibration and software programming for its seven driving modes, but its overall ability to be either plush or sporting is most impressive.

Yet despite its lengthy standard equipment list, for the reasons above it perhaps still seems a fraction too expensive. It might be more focused than an E43 or S6, but it arguably is not as cohesive. That was put into further context when, in the week following this test, we drove a Holden Commodore SS V and found its auto calibration, cabin ergonomics and space more impressive – at half the price.

Still, knowing Lexus, there will be further updates to the GS F. It is closer to brilliance than ever.

RivalsAudi S6 from $170,716 plus on-road costs
Invisible sedan ultra-fast, uber-luxurious but expensive.

Mercedes-AMG E43 from $159,900 plus on-road costs
Engine lacks character, but otherwise a fine executive express.