We've been climbing the narrow, twisting and turning road that winds from Milford Sound towards the Homer Tunnel.
The weather had closed in, forcing Ford New Zealand to abandon plans to fly us in to pick up the BA Falcon XR8s for the drive back to Queenstown Airport. The cars had been driven to Milford the day before by another bunch of motoring writers.
As we wind our way up to the tunnel, the road is damp, not streaming wet but probably slippery enough.
Jacqui Madelin, taking the first driving stint, has opted to leave the traction control switched on. It's against her performance car-driving instincts. She's a quick, keen and competent driver who likes the chassis to be completely at her beck and call, without electronic assistance.
But with a car weighing almost 1800kg and 500Nm of torque and 260kW of horsepower about to be unleashed the instant she stabs the throttle, she figures she'll keep the safety net deployed.
She has no desire to put the big sedan in a roadside ditch, especially when Ford NZ's affable managing director Richard Matheson is riding in the back seat.
The XR8 never puts a foot wrong, and despite its bulk and weight never needs more of the road than a compact 2.0-litre might.
The Dunlops grip the road beautifully. Madelin might be keeping the traction control on, but she's not hanging about and the car's generating plenty of g forces as she pushes it hard into corners.
From the passenger's seat the car seems in its element, cornering with unshakable stability, swallowing the short straights at a gulp. The sports-style seats provide plenty of support. I'm bracing my feet a little but I'm not getting thrown around.
Ford NZ's PR man Ed Finn chose the Milford road for the media launch because that's where the TV commercial for the BA was filmed. That aerial shot looking down on to the car rounding a hairpin was filmed on the final climb to the Homer Tunnel on the Milford side.
My chance at the wheel comes a few kilometres later, this time in an XR8 manual.
As we dash through forests and along lakesides the car is absolute magic. The five-speed shifts smoothly and quickly and is a far cry from the ponderously-shifting manual gearboxes found in older Australian muscle cars. The clutch, though moderately heavy, takes up cleanly and smoothly.
The power on tap provides vivid acceleration. We're country road sprinting, not accelerating from standing starts, but if we were Australian magazine Motor says we'd hit 100km/h in 6.16 seconds. Motor cut out the 0-400 metre dash in 14.40 seconds at 160.4km/h.
At a guess, top speed's likely to be around 230km/h.
The in-gear acceleration is stunning, especially in third where the strong torque makes the engine wonderfully flexible.
In fact, it's the torque which makes the XR8 so intoxicating to drive. It's so meaty and so strong that you don't need to make much use of the gearbox.
Acceleration is a little more leisurely in fifth gear, but in fourth there's plenty of urge. A winding road with moderately tight corners can be tackled with confidence and at speed with the car left in fourth gear.
When the going gets tighter you simply slot the car into third. Second is only for the very tightest corners or when you want to feel the push-you-back-in-the seat acceleration at its most vivid.
Both cars had the Premium brake package and we figure most buyers will opt for these bigger, more powerful brakes. They were certainly up to the job.
As we cycle through the four cars - two manuals, two autos - on the drive programme, taking the journey in 30 to 45 kilometre bites, we come to some firmly-held conclusions.
The manual is better than the auto. It's smooth-shifting and refreshingly light for a car of this type. The auto changes gears brilliantly and the sequential manual mode gives the driver an added sense of control.
But there's a moment of hesitation before the power comes on in the auto that's not present in the manual.
I also felt the sequential manual shifts were less smooth than the older auto transmission which you could shift manually by slotting the lever among Drive, third, second and first.
We're sure the auto would be preferable should you plan to use an XR8 for big city commuting. But on a challenging open road the manual is the only choice.
Then there was the unflappable chassis. It never stumbled, never felt anything less than precise. The steering was direct, positive and well-weighted; the car's turn-in to corners was accurate and instant.
The car never ever felt as heavy or as bulky as it is; and nor did the V8-engine XR8 feel any less agile than the sublime Turbo XR6.
Only occasionally as the auto hesitated before shifting down in a slow corner did you become aware that a big and heavy V8 lurked under that bonnet bulge.
The icing on the cake came on the final run into Queenstown along the wonderful, winding road along the Frankton Arm of Lake Wakatipu.
Here, with four on board, the XR8 was simply sensational, darting along like a thoroughbred sports car. Its grip on the road was phenomenal, it was never caught out even by corners that were sharper than I'd been anticipating. The ride quality was absorbent and supple. The car simply shrank around me, responding instantly to my demands. The chassis' grip and composure were so great I kept braking to a minimum.
The finest moment came on a tightish, wide-radiused, hairpin-like corner.
I braked, turned the car in on a wide, late-apex line, feeding in more lock as the corner tightened. I rolled my foot on to the throttle, pushing it smoothly to the floor.
The car hunkered down and leapt forward. I let out an involuntary whoop of joy. I just couldn't help myself.
On that final run into Queenstown I had more on-road fun than I've had so far this year.
In the new XR8 - and in the 290kW Falcon GT we drove earlier in the year - Ford has created the finest factory-built mainstream sports sedans to come out of Australia so far.
I think the XR6 Turbo is a very special car, but deep down I'm a V8 man and I think the XR8 with its glorious bark at full throttle is even more special still.
This is one fine car.
Mike Stock. Photographs by Ford New Zealand.