The Audi A4 offers the broadest number of models including sedans, station wagons and convertibles using A4, S4 and RS4 designations. Competition in the A4 market is strong but with a base price under $30,000 and Audi optional quattro® full-time all-wheel drive system, the A4 is the most popular car among Audi vehicles. From Audi corporate single-framed grille to the signature taillights, the A4 and its performance-tuned derivates have an attractive, but modest design. The Audi A4 comes with a four-year/50,000-mile warranty and gets an estimated 25-30 mpg on the highway.