Astra Twin Top convertible by November

The Astra TwinTop is finally confirmed for Down Under duties and could even make it to showrooms before the end of the year.

While GM Holden refuses to confirm any details, and insists it is still working through the business case for the car, its dealers are talking openly about the TT and even touting an on-sale date in the back end of October.

The early arrival is unlikely, particularly as there are still stocks of the previous-model Astra convertible in Australia, but GM Holden is keen.

The car is expected to come with a 2.2-litre petrol engine, electronic stability control, five-speed manual and automatic gearboxes, and a price tag close to the current car, which will mean about $45,000.

GM Holden is not likely to follow Vauxhall, which has a 1.6-litre price leader at closer to $38,000 in Britain. The TwinTop is the latest of the new generation of convertibles which have a solid roof - usually metal, but composite in the latest Mazda MX-5 - to make them into a complete coupe when they are not doing convertible duties.

It can easily be added to the local line-up as GM Holden has a commitment on Astra numbers - but not the exact model mix - it takes from Opel in Europe. It has already tweaked the mix this year to introduce the Astra turbo coupe and diesel hatch.

"We have said for some time that we're looking at the possibility of the Astra TwinTop convertible," says GM Holden spokesman Jason Laird. "We think the retractable hardtop would do quite well here. We are still looking at timing and pricing, but it makes a fairly compelling case."

Laird says the TwinTop could create problems clearing the last of the previous model, without going into specifics. And he has ruled out any chance of a TwinTop turbo, although there was a time when the Astra range included a performance convertible. But GM Holden is moving quickly on the latest Astra and knows it would be a summer hit in Australia.

"From the moment we introduced the current car it became the best-selling convertible in the country and has pretty much stayed there," Laird says. "When we introduced the five-door Astra in 2004, we knew we would have the ability to customise the local Astra fleet.

"The trick with Astra is to pick the right cars at any point in time. It's not necessarily about taking every variant, but picking the right ones at the right time."

Meanwhile, the upcoming Holden Epica is going to rock Toyota Australia's fuel-economy drive.

Toyota is pushing the fuel-economy advantages of its all-new Camry and upcoming V6Aurion over the VE Commodore.

But the Korean-made Epica promises to undercut the Camry, which achieves 9.9-litres/100km, according to leaked information from Holden at Fishermans Bend.

The Camry-sized Epica looks likely to run at 8.2-litres/100km with a two-litre engine, according to ADR81/01 trials, with the 2.5-litre model coming in at 9.3-litres/100km.