The Lexus SC430 is a totally different beast. This car is a hardtop convertible. As a hardtop, the car makes no compromises: The ride is quiet and the structure is stiff. With a push of a button it becomes a convertible. You don't even have to undo any latches.
The roof on the SC430 folds in half and stows in the trunk. When you press the button to lower the roof, the windows roll down and the trunk opens. It opens the opposite way, with the front of the trunk (nearest the front of the car) lifting up. After the trunk is open, the roof starts to open, folding in half as it heads for the trunk. The roof folds over until it is fully inside the trunk, at which point the trunk closes. The cool thing about the trunk is that it can still open just like a regular car trunk -- although with the roof down, there isn't much room in there.
Since this roof is fully automatic, there are a whole lot of motors, actuators and sensors required to make it work. The motors that power the roof work in a similar way to those in the Honda S2000. Since the Lexus also has to open the trunk and latch and unlatch the roof, it has a couple of additional motors and actuators to perform those tasks. The folding of the roof is taken care of by a much simpler linkage than in the S2000, though, since the SC430 roof only folds in half.
Having one convertible is (almost) as good as having two cars in your garage. With the top up, a convertible can be as practical as a coupe. But with the touch of a button (and perhaps a few un-latchings), your ride to work can be a whole lot more fun.
For more information on convertibles and related topics, check out the links below.