SERIOUS roadsters are now specialist pieces of kit and Audi is a master of the art of making some of the best.

Its latest creation is a soft top version of the new TT and it has just the right blend of sexiness and sportiness.

Set off with a high tech interior which can be finished in some exotic leather trim the TT Roadster is setting a new benchmark.

And in high performance TTS guise it is more than a match for Porsche's rear wheel drive Boxster.

The new TT Roadster is coming to the UK in May six months after Audi launched the third generation TT Coupe.

Priced from £31,995 to £37,555 the new roadster is some £2,000 more than the coupe and the previous model while the more powerful TTS costs from £41,085 or £42,455 when fitted with Audi's rapid fire S tronic semi automatic gearbox.

All versions have evolved to pack a bigger punch yet be more economical with the diesel TT leading the way.

It is 26 per cent more fuel efficient and now achieves an official rating of 65.7mpg with emissions of 114g/km making it significantly more frugal - and cheaper - than the only other diesel roadster in this league, the Mercedes SLK.

The diesel is the entry level TT Roadster but not lacking in any way.

It's available only as a front wheel drive, six speed manual and in either Sport or higher grade S line trim which is priced from £34,505.

The 2.0-litre engine is one of Audi's new high efficiency ultra diesels and now develops 184ps (up from 170ps in the previous generation roadster) resulting in a 0 to 0 6ime of 7.3 seconds and a top speed of 147mph.

It is a smashing car to drive with a great sound coming from the twin exhausts and the noise is not at all diesel-like, more of a thrum than a chatter.

The amount of mid-range pull impresses and in any gear it moves with purpose while the handling is spot on.

Every TT Roadster comes with Audi's multi-mode drive programme which varies suspension, steering and throttle feel and all have a stop/start system complete with a coasting function to conserve fuel.

The hood is electrically driven and takes 10 seconds to operate, stowing itself behind the cockpit without impinging on the 270 litre boot.

Get caught in the rain - and we did several times while trying out the new roadster - and the roof can be put up on the move at speeds of up to 31mph.

A wind deflector is an option to suppress buffeting and so is additional cockpit heating - including warm air ducts in the seats - for topless driving on colder days.

Audi stays true to the soft top theme for its roadsters and the hood is sturdy, well insulated and keeps noise low. It is also available in three colours, black, grey or beige to fit in with the 10 paint jobs on offer in the roadster range which include bright yellow, red and blue finishes.

It is a good looking car, more angular and athletic than before and has plenty of road presence with a larger grille and LED running lights delivering a distinctive signature.

At the rear is a pop up spoiler which deploys from the boot lip at motorway speeds while a thin strip of red LEDs illuminates across the back of the car under braking.

It all looks very classy when on the move.

The cheapest petrol model costs just £50 more than the diesel and uses a 2.0-litre turbo engine boosts to 230ps which takes 0 to 60 down to 6.2 seconds yet can still return a claimed 47.1mpg in front wheel drive set up.

Quattro versions with their all wheel drive extra grip cost from £35,005 and come with S tronic gearboxes making them quicker (0 to 60 in 5.6 seconds) but only marginally more thirsty at 42.2mpg.

All are massive fun on the road but the cream of the crop is the TTS with its 2.0-litre engine boosted to an incredible 310ps - that's 155ps per litre making it one of the most powerful of its kind and with quad exhausts it makes a stupendous roar under acceleration.

The TTS is due to arrive in June and in S tronic form costs from £42,455 undercutting and outperforming the likes of the BMW Z4 M Sport, the AMG Sport SLK and the Boxster.

At 4.9 seconds 0 to 60 it is the quickest of the lot and the extra traction from the quattro system makes it feel absolutely sure footed when going through its paces. Audi's variable power steering has now come of age and delivers masses of feedback to enhance the TT's considerable agility.

Audi claims the TTS is good for 40.9mpg with a CO2 output of 159g/km. On our drives we managed 30mpg from the TTS and 44 to the gallon from the diesel.

But what sets the new TT apart is the cockpit with Audi's virtual instrumentation - a feature none of the alternatives possess.

Instead of conventional dials on the dash the TT is fitted with a large high definition screen behind the steering wheel which shows everything from the speedo and rev counter to Google Earth sat nav imagery.

Driving any of the new Audi roadsters is motoring fun of the highest calibre but the TTS is genuinely pushing the performance envelope for sub £50,000 sports cars and nudging into Jaguar F-Type and Porsche 911 territory.