new versions of the Impreza

Considering it took Subaru nine years to expand from four to five global model lines, you might think it will be a long time before there is another bout of significant activity from the Japanese car maker.

But the opposite appears to be the case.

Subaru will build almost 600,000 cars this year. As an independent, that makes it too big to be niche, and too small to be secure. It has mid- to-long-term plans to increase sales to 800,000 a year.

An all-new Impreza hatch and sedan - including the iconic WRX turbo - are expected late next year. In 2008 we'll see the third-generation Forester and in 2009 the next Liberty/Outback.

But just as significant for Subaru's global growth target will be the debut of turbo-diesel technology. It should first appear in Europe late next year, where compression ignition engines now dominate most markets.

First up should be a 2.0-litre four-cylinder boxer and later a six-cylinder 3.0-litre boxer. These engines are expected to lift Subaru's European sales performance in the next few years and account for most of its increased global volume.

There is certainly potential for improvement. Subaru's annual sales in Australia outnumber the combined sales of Germany, France, Britain, Spain and Switzerland.

The 2.0-litre turbo-diesel should first appear in the Outback, arriving in Australia late in 2008 or early 2009. Petrol engines aren't being ignored, with a bigger 3.6-litre six-cylinder said to be under development, along with improved turbos that will help to power the next-generation performance models.

Further out, a newly formed alliance with Toyota - replacing an unsuccessful relationship with General Motors - has given Subaru access to hybrid technology. But don't expect to see a petrol-electric Subaru this decade.

And what of an expansion beyond five model lines? According to Australian managing director Nick Senior, the emphasis will be on the styling of the next generation of existing models, starting with Impreza.

Versatility and flexibility will also become a design imperative. Senior revealed that Ikuo Mori, the new president of Subaru's parent, Fuji Heavy Industries, had reopened studies into several projects aborted by the previous leadership. These include a vehicle based on the Liberty platform that is similar in concept to the Mercedes-Benz B-Class compact people-mover.

"It is being looked at again," confirmed Senior. "It is one of a number of cars with potential."