Once upon a time, S was for Audis what M was for BMWs. A decade ago Audi took an A4, added a pair of turbos to the V6, stiffened the suspension, plus-oned the alloys, and tagged the result the S4. A special driving experience that became more special (if less moddable) when the 250-horsepower turbo V6 was replaced by a 340-horsepower V8 a few years later. The A4 was redesigned for 2009, and this year there’s a new S4. The V8 has been tossed in favor of a supercharged 3.0-liter V6 that kicks out 333 horsepower. Is the resulting car worthy of the S?