The Audi S4 is one of the best looking sedans on the planet. It is also one of the fastest! Powered by Audi's famous 2.7 litre twin turbocharged V6 engine. This engine gives the S4 258hp and 250 ft lbs. This means the S4 can go 0-60 in only 5.5 seconds, making one of the world's fastest mass production sedans. This sports sedan has a top speed of 156mph, which is perfect for the Autobahn. The S4 has a base price of US $ 39,000, which is very low compared to the BMW M5 and the Mercedes E55 AMG. This is one hell of a sports sedan!