100 (C4)

The Audi 100 C4, produced from 1990 to 1994, was the fourth and final generation of Audi's flagship sedan to bear the '100' name. Designed by Hartmut Warkuss, it refined the aerodynamic principles that had made its predecessor, the C3, one of the slipperiest production cars of the 1980s. The C4 achieved a drag coefficient of just 0.30, contributing to excellent fuel efficiency and refined high-speed cruising — qualities that were increasingly important to European executive car buyers.

The C4 was offered with a wide range of engines, from economical five-cylinder diesels to the potent 2.8-liter V6 and the range-topping 4.2-liter V8 in the S4 and S6 variants. The V8 model, producing up to 290 horsepower in S6 specification, was paired exclusively with Audi's legendary quattro all-wheel-drive system and demonstrated that Audi could compete with BMW and Mercedes-Benz on performance as well as refinement. The five-cylinder turbocharged engine, a signature Audi powerplant, was also available in various states of tune.

The C4 generation introduced several important features to the Audi lineup, including the procon-ten passive safety system (which pulled the steering column forward in a frontal collision), a fully galvanized body that offered outstanding corrosion resistance, and improved interior materials and build quality. Available in sedan and Avant (estate) body styles, the 100 C4 offered practicality and versatility alongside its dynamic capabilities.

With nearly one million units produced, the C4 was a major commercial success for Audi and played a crucial role in the brand's continued upmarket push during the early 1990s. It was the last Audi to use the traditional numeric naming convention before the switch to the letter-number system (becoming the A6 C4 from 1994 with a facelift). Today, the Audi 100 C4 is appreciated for its understated elegance, robust construction, and the availability of powerful quattro variants that offer genuine all-weather performance at affordable prices.