Earlier this month, we brought you the first spy shots of the soon-to-be revealed Opel Astra-based convertible model (to be sold as a Vauxhall in the UK) wearing its production body while undergoing hot weather testing in Southern Europe with its top closed.

If you happen to be wondering what the prototype version of the new Opel model will look like with its traditional fabric roof tucked neatly away under a tonneau cover behind the rear seats, we have good news for you as our scoopsters spotted the firm’s engineers enjoying the summer weather on the Nürburgring.

Neither Opel nor Vauxhall have announced the car’s name yet, but company officials have confirmed that it won’t use the Astra moniker, and this despite the fact that the four-seater model will use the same platform, powertrains, interior and even the same design language of the compact model.

That said, the engine options will mirror those of the Astra and Astra GTC models and will include GM Europe’s all-new 1.6-liter turbocharged four-cylinder gasoline unit with direct injection and Start/Stop, which will be offered in various states of tune producing up to 197hp (200hp).

This new powerplant delivers more power than the current version while at the same time, achieving greater fuel economy and lower CO2 emissions.

The as-of-yet unnamed compact convertible model will join the new Adam premium city car on Opel’s stand at the Paris Motor Show in September. European sales will begin in spring of 2013.

GM has not said if it will offer the new drop top model in the States as a Buick.

Photo Credits: CarPix for CarScoop

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