The BMW M3s We Never Got

For a quarter of a century, the BMW M3 has been the archetypal transportation choice for the well-heeled German-car enthusiast looking for a sport coupe with four usable seats. Although the M3 has evolved greatly over time-growing in cylinder count from four to six to eight along the way-each M3 arguably represents the best sedan-based driver's car of its time. But there's one more thing all four generations of the M3 have in common: each M3 came in an even more potent form that, sadly, didn't come to America. We went to Munich to drive them back-to-back and see what we've been missing. Generation I: E30 Sport Evolution
The final evolution of a sports car revolution. The original M3 wasn't designed to sell, it was designed to race. Homologation rules dictated that, in order to take their vehicles racing in various touring-car series, manufacturers had to produce 5000 street-going versions of the race car. That explains the story of the M3's appearance on public roads-and in the United States, the E30-series M3's story ends there. But there's more to it. Remember that the E30 M3 was a brass-knuckled backhand to the Mercedes-Benz 190E 2.3-16, and these two cars were embroiled in one of the most fervent racetrack rivalries of their time. To remain competitive season after season, the dueling Germans invested in systematic tweaking. Evolutionary changes were permitted-so long as 500 copies of the new model were built for public consumption. BMW and Mercedes each produced three updates of their cars, and the ultimate BMW was the 1990 M3 Sport Evolution. To remain competitive with Mercedes, the M3's 2.3-liter four-cylinder was bored and stroked to 2.5 liters. Horsepower and torque increased accordingly. So did vibration, a side effect exacerbated by the fitment of a lighter flywheel. Sodium-filled exhaust valves and piston oil squirters helped keep the new engine ticking, and bigger intake valves and more aggressive timing and lift helped it breathe. An automatic transmission was unthinkable-the Sport Evo kept the dogleg five-speed from the regular Euro-spec E30 M3.