It's always fun to see the engineering behind hard top convertibles. The latest member of the breed comes from Lexus in the form of the 2009 IS250C. This new derivative of the IS250 sedan sports a three-piece aluminum roof that retracts in a "world's fastest" 20 seconds. Video proof of the event taking place has been released and we've embedded it after the break. The new 250C's most logical competitor comes from BMW, whose 3 Series convertible features a folding hard top of its very own. When the new Lexus goes on sale next summer in Europe, followed shortly thereafter in the United States, it will offer buyers a replacement for the expensive SC 430, which is set to make a graceful exit from the marketplace in short order.