Audi's wicked new RS4 Cabriolet will join its sedan and Avant (wagon) stablemates on sale in the first quarter of 2007. Just 25 examples will be available, at $187,500 apiece. Audi’s hottest ever cabrio is powered by the same 309kW/430Nm 4.2-litre V8 that motivates the RS4 sedan and wagon.