It's seven degrees outside and there's no wind. There's a half-kilometre of open road ahead that seems to say: "C'mon! Bring it on..."
And there's 3.6 litres of turbocharged, purring Porsche at my back.
Bring it on indeed.
Left foot on the brake pedal; right foot on the accelerator to build up some revs. The Porsche becomes a Doberman straining at its leash, desperate to chase after some hapless prey.
So I loose the leash and stomp that throttle for all it's worth.
The acceleration is instant, brutal. Not a hint of wheelspin from the all-wheel drive. One moment it's here and the next it's hyperspaced to a point somewhere up ahead. The car flashes forward with a force and intensity that takes my breath away.
An electronic brain hooks second gear and by the time my eyes flick to the speedo the needle has already sped past 100km/h.
Another gear, another mad rush and then we're flying across the quarter-mile finish line and it's time to hit the brakes.
If I'd been dicing a BMW M5 or a Mercedes-Benz SL65 AMG - formerly the two quickest cars ever tested by this publication - they'd both be in my mirrors now.
Because the new sixth-generation Porsche 911 Turbo has just romped from rest to 100km/h in 4.2 seconds, the quickest we've ever clocked at Joburg altitude and not far off Porsche's 3.7 second sea level claim.
It's also done the quarter-mile in just 11.7sec, the first car that's ever managed a sub-12 in our hands. What makes it doubly impressive is that this is an automatic car and the two-pedalled Tiptronic S version of the 911 Turbo is in fact two-tenths quicker to 100km/h than the six-speed manual.
What the figures don't tell you is how easily the Porsche reels them off. To post sub five-second sprints the M5 uses a computerised launch control system which needs a few minutes' recovery time between each run. The SL65 AMG has so much tyre-shredding torque that it takes a lot of practice not to deposit stripes of time-sapping rubber in a fast launch.
With the 911 Turbo Tiptronic, you simply mash the throttle and let 'er rip. Time after time, effortlessly, it reels off nearly superbike-challenging sprint times.
Aside from the low volume Carrera GT supercar whose production has now come to an end, the 911 Turbo is the ultimate Porsche.
The starring role in this new halo model is played by a new generation flat-six turbo engine, which wields 353kW of power and 620Nm of torque (680Nm if you press the overboost button) - a considerable leap over the 309kW and 560Nm made by the last generation 911 Turbo.
Commuter-cum-supercar
All the torque is on call from low rpm, making for spontaneous power delivery that's almost completely lag free - even at Jo'burg altitude. Say thank you to a variable turbine geometry turbocharger for that, the first time such a device is being used in a petrol engine.
The genius of this German sports car is how accessible it is. It's a genuine commuter-cum-supercar with a benign, easy-to-drive nature in slow-moving traffic, with only its stiffer-than-usual suspension hinting at anything out of the ordinary. It has rear seats big enough for young kiddies, sumptuous leather upholstery and all the bells and whistles of a luxury sedan.
But when the road opens up it can accelerate as if the hounds of hell were after it, and they'd get tired pretty quickly chasing the 911 Turbo's 310km/h top speed.
The car's directional stability and general calmness at such velocities is remarkable. No wandering in the lane, no vibrations; it just smoothly rips through the airstream and renders the scenery a rushing blur. It's ferociously rapid through the gears too, with a solid punch of pace whether you thwack the throttle at 120km/h or 220km/h.
But on the subject of high figures the 911 Turbo's no fuel fairy either, quaffing a greedy average of 17.8 litres/100km.
Sonic satisfaction
Acoustically, the car doesn't really rock your world and the engine note's a bit subdued for a sports car. For a passionate howl the Porsche you want is the GT3. The most prevalent sound in the 911 Turbo, the loud roar of its wide tyres, is not a particularly pleasing one.
But sonic satisfaction is quickly relegated to the back burner when you get to experience G-forces such as these and the 911 Turbo is just as good at braking and taking corners as it is at running away from an M5 in a straight line.
Our test car was fitted with optional ceramic brakes, identified by yellow calipers instead of the red ones that clamp the standard steel discs. Besides offering a longer service life, these pricey ceramic discs stop the car with real meaning. Any car that can emergency stop from 100km/h in under three seconds is very good; the Porsche did it in 2.5.
Today's 911 Turbo has a plethora of electronics to help it go through corners faster and safer, including Porsche Active Suspension Management (PASM) that stiffens the dampers in corners, traction control, and all-wheel drive that continuously varies the front to rear power split.
Consummate driver's car
Yet all these electronic nannies fail to dilute the raw driving experience and it's not until you've driven this Porsche back-to-back with another sports car that you realise just how good it is.
We'd just tested an Aston Martin Vantage which had felt fast and sure-footed but the Porsche made it seem almost heavy and clumsy. The crispness of the German car's steering, the way it goes through turns with ferret-like agility, the way it feels much ligher than its 1620kg, it's the consummate driver's car.
There are more powerful sports cars around but I doubt there are more than a handful that would keep up with the 911 Turbo in a twisty mountain pass.
For all its road-clinging ability the German missile delivers a fairly comfortable ride by sports car standards. Firm, yes, but it cruises over rough tar with a fluent, supple ride that doesn't threaten to jar the steering wheel out of your hands nor the Prada sunglasses from your brow.
It's low, however, so driving in multistorey parking garages needs to be tackled with extra care lest you scrape the spoiler.
Large spoiler
If I have one thing against the 911 it's that it doesn't have the exotic cachet of some supercars. Park it next to a Ferrari or Aston Martin and it seems almost ordinary. The 911's shape has been around, basically unchanged, for four decades, while the cabin styling is also a bit sterile.
But there are elements to tell you this is no garden variety 911 such as the specially styled 19" mags, the LED indicators in the front bumper, and a large rear spoiler which is not just jewellery but aids downforce by automatically raising itself at higher speeds.
The R1 885 000 price tag also makes no bones about where this Porsche sits in the pecking order.
SUMMARY
Amazing pace, how sweet the thrill. The sixth-generation of Porsche's iconic 911 Turbo is a supercar that delivers fearsome pace and fantastic handling with an easy-to-drive nature.