MINI beware! The forthcoming Audi A1 Cabrio should set the cat amongst the pigeons.

We first got to see Ingolstadt's new A1 mini-car last October in the guise of the MetroProject, with the production version expected in 2010 to rival MINI in the supermini class.

The drop-top version has been rendered in new images by Auto Express to look a bit like a compacted RS4. It should debut at the Frankfurt Motor Show in September 2009 but the magazine has already revealed exclusive details about the topless A1.

It features a more complex roof mechanism than the MINI Cabrio's: an electrically-powered hood that folds into the boot instead of sitting on top of the car. But with the two-seater featuring no rear bench, there should be sufficient packing space.

Resembling the marque's existing models, it's clearly an Audi with the familiar grille, and the flared wheelarches nicked off the TT Cabriolet.

At the back, the tailgate is split above the lights by a strong line, while the trapezoidal bumper insert is straddled by twin integrated exhaust pipes.

It should be typically fully-specced, featuring the latest Multi Media Interface (MMI), with the interior distinguished from other small Audi's by unique interior trim combos.

Engines are expected to include both 104kW and 127kW 1.4 TSI turbo and supercharged units. A six-speed double-clutch gearbox will power the front wheels — there's no Quattro four-wheel-drive system.

The rest of the engine line-up should include a 112kW 1.8 turbo engine an entry-level 76kW 1.6, and two 2.0-litre TDI diesel engines rated at 104kW and 127kW.

The range-topping S1 gets the same power unit as the 195kW S3 when it arrives in 2011.