Audi TT Roadster 2015 review

Chopping the roof off a sportscar and turning it into a drop top may seem straightforward enough, but convertibles are in fact really hard to make.

Your car's roof and the pillars that hold it up do more than keep the rain off, they're an integral part of the vehicle's core structure.

Our European correspondent John Carey describes it best, likening it to taking the lid off a shoe box.

Explore the 2015 Audi TT range

• Audi TT Coupe 2015 review
• Audi TT Roadster 2015 review
• Audi TT 2015 review
• Audi TT Sport 2015 review
• Audi TT Roadster 2015 review: Australian drive

Twist the box with the lid on, and it gives more resistance because, together, they're stronger. Twist the box with the lid off and it easily contorts.

For drivers to have the freedom of the wind blowing through their hair, engineers bolster the underbody with so much extra strengthening they could probably build a bridge with the same materials. Okay, so that's a slight exaggeration, but you get the idea.

Sometimes car companies get it right, and sometimes they add all that extra weight (in this case 90kg, from 1335kg-1425kg) and yet seem to make no improvement.

Which is why convertibles remain an engineering challenge, to make sure a car doesn't turn into a blancmange when you turn into a driveway.

That's why one of the first things you read about convertibles in road tests is whether or not they feel like they're going to shake themselves apart.

Having driven the roadster version of the highly regarded TT Coupe we can report that, well, it's fine. Actually it's surprisingly good.

And that's despite the extra trickery of a folding soft-top that takes just 10 seconds to open or close -- and can be operated at speeds of up to 50km/h.

After spending 500km behind the wheel of a roofless TT, dare I say it but I couldn't pick the difference with the coupe.

Now we've addressed that pressing issue, here's the fun stuff you need to know if you're thinking about buying one of these.

Firstly, the awesome digital dash display (which Audi calls a "virtual cockpit") is standard on the new Audi TT Roadster.

The entire instrument display in front of the driver -- where the speedo and other vital signs are normally positioned -- is a digital widescreen.

At the touch of a button you can switch from a normal display to one dominated by a widescreen view of the satellite navigation map and instructions, with the car speed and fuel reserve displayed either side.

Or you can have a large speed readout and a small map display, or a few other options. It's genius.

As with the coupe, the TT roadster retains the high quality interior finish. Some passengers found the design too plain, others liked the simple approach.

Me? I couldn't figure out how to point the aircraft engine-style air vents the right way until someone pointed out the little nib on the alloy ring that surrounds each one.

And the radio was a bit annoying. The premium sound system in the dearer models is superb (way better than any previous Audi, which tended to blunt the volume or couldn't handle extended use at high volume). But the first batch of TTs sold in the first few months in Australia have a gremlin that Audi is in the process of fixing.

The car can't remember which radio station you were listening to the last time you were in it.

So you start the car literally to the sound of static. How such an engineering oversight could make it all the way to production and then to showrooms is a mystery. At least to Audi.

But a fix (which involves an Audi dealer plugging a computer into the car and rebooting) is apparently around the corner.

One more gripe: there is no rear camera on the new TT, either standard or as a dealer-fit accessory.

I'm not sure which planet Audi is on, but when a rear camera is standard on a $14,990 hatchback (and as of this week a $15,990 Skoda, which is owned by the giant Volkswagen-Audi Group), there is no excuse for it to be missing on an $81,500 car.

Fortunately, sanity will prevail and Audi will fit a camera to the TT by the end of the year. But someone still deserves a lashing for the oversight in the first place.

So it's a relief to find that the rest of the car is pretty damn good.

Despite riding on low profile tyres, the TT Roadster won't break your back. In fact, it's gentler on your body than a sportscar with this level of grip and agility ought to be.

The steering is well weighted and precise in feel. The brakes are responsive but not too sharp.

There are five driving modes ranging from "I'm stuck in traffic" to "get me out of here"

The acceleration -- except for the initial delay from rest that is a trait of twin-clutch automatic gearboxes -- is seamless and energetic from low revs.

It does practically everything you could ask of it. There is a button to make it a bit louder when you're in the mood for it, and a button to make it quiet when you're not.

There are five driving modes ranging from "I'm stuck in traffic" to "get me out of here", and then another mode that allows you to tailor the steering, engine and suspension settings. Tech geeks and car geeks alike will love it.