DESPITE being essentially a superseded FPV GT by another name for the princely sum of $45,490, it is a measure of how impressive the new XR6 Turbo is that the new XR8 is no longer the flagship of Ford's Falcon range – either in performance or on the price list.

The FG XR8 may well come with the same 290kW/520Nm 5.4-litre DOHC Boss V8 that FPV's GT ran before it was upgraded to 302kW/540Nm (and which currently costs significantly more at $62,210) – and it may well deliver 20kW more power and only 10Nm less torque than the 6.0-litre Holden Commodore SS, which is $200 cheaper and now comes standard with six airbags instead of the XR8's four.

But the new XR8 faces stiff competition not only from its direct rival at Holden, but from within its own stable. The FG XR6T delivers 270kW (matching the current FPV F6 engine) at 5250rpm and 533Nm of torque from as little as 2000rpm – and all the way up to the XR8's peak torque engine speed of 4750rpm.

Ford does not supply official acceleration figures, but while all claimed performance figures are achieved on premium unleaded fuel, the XR6T

What's more the XR6T can also run on standard unleaded and returns a combined average fuel consumption of 11.1L/100km, compared to the XR8's 14.0L/100km figure (both in automatic guise), which is exactly what both cars returned on this week's varied 450km launch drive.

To add insult to injury, in an apparent acknowledgement that the final (and finest) iteration of Falcon's 48-year-old inline six plays second fiddle to no engine, the XR8 no longer carries its traditional $1000 price premium over the XR6T.

Real-world driving backs up the comprehensive drubbing the XR8 takes on paper.

Of course, the XR8 comes with the same comprehensively redesigned, lighter and double-balljointed front suspension as all FG Falcons, as well as an even sharper, sports-tuned version of the forward-mounted steering rack with variable-ratio steering gear, which gives it a much-needed boost in both agility and stability.

Requiring much less correction to maintain a straight line and offering even greater levels of response as you wind the steering lock on, the XR8 now points more like the sports sedan it is, rather than the lead-tipped arrow it was until now with its cast-iron-blocked V8.

The automatic transmission recalibration work is just as welcome as the new six-speed manual transmission's triple-synchro treatment for first gear. And, riding on 20mm-lower XR suspension that is appreciably firmer but still offers a decent ride on all manner of surfaces, the more nimble new XR8 lacks the diagonal pitching for which it was previously infamous.

But the new XR6T steps up even more in handling terms, understeering less at the limit thanks to its better front/rear weight bias and always feeling more willing to change direction and hold a given cornering line. A back-to-back handling comparison will show whether Holden's SS matches the XR8's new-found body control.

Combine the gruff-sounding 5.4-litre Ford V8 – which is no match for the Holden SS's dam-busting Gen IV V8, revs begrudgingly past 4000rpm to a lowly 5500rpm redline and doesn't feel all that much quicker than the outgoing 260kW model – and the new XR8 simply feels old-school next to both its fiercest rival and the stunningly effective new XR6T.

And we could not really discern any real difference in exhaust note throughout the rev-range, despite the fitment of a new semi-active muffler.

On the plus side, the new Falcon's classy centre information display is a world ahead of the SS Commodore's naff-looking, red-illuminated centre console gauges and the FG Falcon's packaging advantages over the Commodore are many, including a bigger boot with 60/40 split-folding rear seat, plus more head, shoulder and hip room.

As the only V8-powered FG Falcon sedan now available, perhaps the fact it is far easier to get into and out of than before, as well as offering better visibility, will tempt die-hard Ford V8 fans into the newest XR8, which now finally includes front seats that are low enough to suit all manner of body sizes.

There is no doubt the latest XR8 is a big dynamic step forward from its predecessors and a far cry from the circa-200kW 5.0-litre Windsor V8-engined XR8 the previous-generation Falcon AU range was launched with a decade ago.

Times have changed, however. While the FG XR8 is a more finely honed example of Ford's premium V8 sports sedan than ever, and in isolation is still the tool of choice for those who believe there is no substitute for a Ford V8, it has not kept pace with the opposition – let alone its own more efficient turbo-six XR sibling that makes it feel so dated.

But at least Ford no longer demands a premium for it.