In sadly autobahn-free Australia there's only one speed measurement that truly counts, and that's the flat-pedal sprint to 100km/h.

Sure, there's a smattering of expensive exotica capable of flying top speeds of 300km/h (and then some). And that looks great on paper, but unless you happen to live on the main straight of a racetrack, the happy antics of our radar-toting constabulary will see your licence shredded faster than you can say "not guilty, your honour".

But the race to 100km/h is open to everyone. Even more importantly - and if you pick the right road - it's entirely legal.

So let the below be your guide to five of the fastest cars just about any amount of money can buy.

1. Budget: $50,000

• Car: Subaru WRX STi
• Price: $49,490
• Speed: Zero - 100km/h: 5.2 secs

As popular with ram raiders as they are deeply unpopular with the police chasing said ram raiders, the Subaru WRX is a car with something of a questionable reputation in Australia. But chequered past or no, there's almost no other vehicle that offers the kind of bang-for-bucks performance as the infamous "Rex", which is why it was so damn popular with the balaclava set in the first place.

The meanest of the lot is the high-performance STi version, and lurking under its gaping bonnet vent is a turbocharged 2.5-litre engine that will produce a whopping 221kW and 470Nm. But the thing that makes it so formidable is the way it delivers that power to the road below, namely in great big handfuls sent to all four tyres at once.

And that's enough to see the STi knock off the zero to 100km/h sprint in a sprightly 5.2 secs - more than enough to rattle a lot of far more expensive cars.

2. Budget: $100,000

• Car: Mercedes-AMG A45
• Price: $77,900
• Speed: Zero - 100km/h: 4.2 secs

Mercedes once reserved the mad-house AMG treatment for its biggest and baddest brutes, so when it decided to wave that performance wand over its smallest model, the result was always going to be something special. How special? Mercedes literally redefined the concept of a "hot hatch" with its launch-mode-equipped road weapon, with the bristling A45 officially the world's fastest production hatch.

Powered by a thunderous and turbocharged 2.0-litre engine, the A45 will scream (and we mean that literally, with the smallest AMG equipped with the kind of booming exhaust that can alter weather patterns) to 100km/h in a blistering 4.2 seconds. And with a touch over $20k change from your $100k budget, the A45 is a performance bargain to boot.

3. Budget: $150,000

• Car: BMW M3 Competition
• Price: $144,900
• Speed: Zero - 100km/h: 4.0 secs

BMW's iconic M3 has long been considered one of the world's benchmark performance sedans, and the latest iteration is every bit the rolling, rear-wheel-drive hero you'd expect. But the German brand has dialled up the crazy even further with its new Competition model, squeezing an extra 14kW from its twin-turbocharged, 3.0-litre V6 engine, which now fires out a total 331kW and 550Nm.

That power is fed through two tortured rear tyres before being forced into the tarmac, propelling this luxe lunatic to 100km/h in four seconds flat. That's the kind of speed that, until very recently, was confined to two-seat supercars from Italy. But the BMW manages it with a backseat. And a boot. And child-seat attachment points.

4. Budget: $200,000

• Car: Nissan GT-R
• Price: $190,750
• Speed: Zero - 100km/h: 2.7 secs (claimed)

Less a car and more a cut-price teleportation device, the GT-Rs of old earned the nickname "Godzilla" for their monstrous and unrivalled performance credentials. The long-time supercar slayer was completely reimagined in 2007, and has been tickled and tweaked in the years since to produce even more power, and better acceleration times.

It's powered by a truly epic twin-turbocharged 3.8-litre V6 that will fire 419kW and 632Nm to all four wheels, aided by a huge suite of technological wizardry. The GTR's last official sprint time was quoted at just 2.7 secs - fast enough to put the frighteners on supercars wearing price tags at least twice that high. Just how achievable that time is, however, is subject to some debate, with real-world testing recording a number closer to 3.0secs. But really, you're splitting high-speed hairs at that point.

5. Budget: $250,000

• Car: Tesla P100D
• Price: $258,708
• Speed: Zero - 100km/h: 2.7 secs

For a nation as obsessed with the petrol-incinerating acceleration of the trusty V8 engine as our own, the fact that the fastest production car on the planet runs purely on electricity is a kind of motoring blasphemy.

But Tesla tore up the petrol-powered rule book with its all-electric Model S, and the fastest of the lot is the P100D. The "100" part stands for the size of the battery pack fitted to the sleek sedan, with 100kWh available to feed two electric motors, one for the front wheels and one for the rear ones.

And due to the quirks of the electric engine (which we won't delve into here), every ounce of that power is available from exactly zero kilometres an hour. And that means this super sedan lunges forward like nothing that's gone before it, accompanied by an eerily silent soundtrack.

6. Budget: Sky's the limit

• Car: Porsche 918 Spyder
• Price: $1.5 million
• Speed: Zero to 100km/h: 2.6 secs

At a cheeky $1.5 million, the Porsche 918 Spyder ain't cheap. But that hasn't stopped well-heeled punters across the planet snapping up all 918 examples before any could make their way to Australia.

It could have something to do with the 2.6 sec zero to 100km/h sprint time produced by this most hyper of hypercars. The 918 Spyder is equipped with a 4.6-litre V8 that will deliver a not-insubstantial 447kW to all four tyres. But take into account the two bonus electric engines that contribute a combined 210KW to the final tally, and the numbers start to look a little silly.

Add to that the maximum 1280Nm of torque, and the 918 Spyder doesn't so much accelerate as it does disappear into the future like you've engaged warp speed, with 100km/h passing by in just 2.6 secs.

This story first appeared at Executive Style.