We reviewed the BMW M3 Coupe with a manual transmission and the full load of cabin tech back in April, but we couldn't pass up the opportunity to test out another one, this time the 2008 BMW M3 Convertible with the new double-clutch transmission. Although our convertible M3 lacked the cabin tech options, not even having the programmable M button on the steering wheel, it still proved a remarkable car to drive with all the performance capabilities... // CNET News

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The DCT is a manual transmission with two gear shafts, each with its own computer-controlled clutch. When driving, one clutch will engage a gear on its shaft, while the other clutch sits ready to engage the next up or down gear, with the computer determining the most likely next gear you will want. In manual mode, you can choose to shift up or down using steering wheel paddles or the shifter. Because the computer controls the clutches, there is no clutch pedal. The car also has an automatic mode, where the computer determines when to shift up or down. The BMW M3 Coupe we tested had a standard six-speed manual. The double-clutch transmission has seven gears.

However, the DCT isn't the only difference between these two cars. The BMW M3 Coupe gets a carbon fiber roof, while the BMW... // CNET Reviews

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We took the car on the same route we drove the M3 Coupe, a series of long, winding roads north of San Francisco, then back down along the coast on Highway 1. The double-clutch transmission definitely changed the driving experience--we kept it in manual mode and spent more time shifting between second gear and third gear than we did with the manual transmission M3 Coupe, which was content to run in third gear for all but the tightest turns. Shifting with the DCT is effortless, merely requiring a pull on the left paddle for downshift and the right for an upshift.

As an M car, the M3... // CNET Reviews