BMW will unveil the Mini Convertible in January 2009 at the Detroit Auto Show, with sales to begin later in the spring. The latest spy shots reveal that the differences between the old and new versions of the Convertible are minimal, and the new car retains the current model’s canvas folding roof.

What you see in the spy picture (judging by the paintwork mostly) is a Cooper S model, which will uses the 175bhp 1.6-liter turbocharged engine. This should be good for a top speed of 140 mph and make the 0-62mph sprint in 7.1 seconds.

In europe, the Convertible will be available with a diesel option coupled with BMW’s Efficient Dynamics technology for the first time, using the Cooper D’s 1.6-liter 110bhp engine – which should be able to return a combined fuel economy of over 70mpg.

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