New Subaru WRX the fastest ever

Rev-heads rejoice! The new Subaru WRX promises to be the fastest ever. But the concept car unveiled at the New York motor show overnight still had to be pushed onto the stand as it didn't have an engine -- or an interior.

Japan’s favourite performance car -- which has regained its styling mojo after the company brought in younger designers -- was unveiled ahead of a production car debut at the Tokyo motor show this October.

The new Subaru WRX will be faster than before even though the new generation turbocharged 2.0-litre engine will be smaller and more fuel-efficient than the 2.5-litre turbo in the current model.

For the first time in its 20-year history the WRX will have a completely unique body, rather than a modified version of the regular Impreza model. As a result, it will drop the Impreza name.

The fourth-generation Subaru WRX will likely debut as a sleek four-door sedan, which could lead to a two-door coupe at a later date. The wagon and hatch are expected to be discontinued.

Subaru says it investigated hybrid power for the new WRX (as Mitsubishi has done for the next version of its rival the Lancer Evolution) but insiders say this has been ruled out for now because the extra weight of the electric motor and battery pack would blunt performance.

To that end Subaru will make the WRX available with a carbon-fibre roof on the top-end STI model, while all variants are expected to come with an aluminium bonnet, boot and front fenders -- which should lead to a weight reduction of about 100kg compared to the current model.

Subaru insiders say a six-speed manual transmission will be standard as a dual-clutch auto has not yet been developed. Instead, a CVT auto will likely back the self-shifting model.

Subaru executives at the show would not disclose details about the new WRX but did promise better performance.

The production version of the new Subaru WRX is expected to be unveiled at the Tokyo Motor Show this October. It should arrive in Australian showrooms early next year priced about $40,000.

This reporter is on Twitter: @JoshuaDowling