I have decided to treat the M3 separately from other 3-series models. The M3 models differ quite a bit in price, engine, and sometimes design from the regular models.
The first M3, based on the E30, was introduced in 1985 as homologation model for motorsports. It has little in common with the regular two-door model, with its widened fenders and raised trunk lid with spoiler, and a 2.3l 16-valve four-cylinder engine. It was extremely successful in what was maybe the golden age of touring car racing. Several successively more powerful versions were made (with displacement raised to 2.5l), in very limited numbers. The E30 is the rarest and thus most sought after M3.
The E36-based M3 lost its motorsports pedigree. It was from the outset developed as the top-end model in the E36 range, based on the coupé. It was initially equipped with a 286hp 3.0l engine. In 1995, the displacement was increased to 3.2l and the power to 321hp, now coupled to a six-speed gearbox. The same time, the SMG (sequential manual) gearbox was introduced in 1996, the first time that such a gearbox was offered in a production car.
While the E36 M3 looks indistinguishable from a standard E36 coupé with M package, BMW decided to give the E46 M3 some design features not available on the normal models: a “power dome” bulge on the hood, air outlets behind the front wheels, and four exhaust pipes, resulting in a clearly distinguishable and aggressive look. The engine was an evolution of the E36’s engine, with a bit more displacement and power (343hp). The SMG gearbox was once again available, too. The E46 M3 remained practically unchanged through its successful production run. A limited edition was the M3 CSL, which was clearly aimed at the trackday enthusiast (and collector). It was lightened, by modifications like the removal of the rear bench and a carbon roof, and power was increased to 360hp with a different airbox. This all came at a steep price increase – in Germany, the CSL was €85,000 vs. €55,000 for a standard M3 without options. The E46 M3 was used in the American Le Mans series, but with a completely different V8 engine, a move that created an outcry from the outclassed competition.
The E9x M3 retained the design cues introduced with the E46. In a move that caused some criticism from BMW lovers, BMW dropped the straight-six and moved to a V8 engine, an option not offered for the regular models. I believe that BMW had no choice, since the competition (e.g. Audi, with the 344hp S4 and 420hp RS4) had already moved to V8s with more than 4l displacement and 400hp. This was before turbochargers became the norm (with BMW taking its first steps in this direction on the 335i), so a 4.2l V8 was the only way to achieve 421 hp.
The performance of the E30 may sound a bit disappointing today – around 230 kph maximum speed with 0-100 in 7 seconds isn’t that exceptional today, but one has to remember that this was 30 years ago. The E36 kicked it up a notch. The 3.2l model is quite quick even by modern standards, with the top speed limited to 250 kph and a 0-100 time of 5.5 seconds. The E46 offered only a slight power increase while gaining some weight, so performance stayed basically the same. The E9x finally managed to crack the 5s barrier.
E36 through E9x models offer sports car performance at significantly lower prices than Porsche, while being sportier than comparable offerings from Mercedes-Benz/AMG (built more for comfort) or Audi (heavy, four-wheel-drive, poor weight distribution thus suffering from understeer). Quite reliable mass-production technology and reasonable maintenance costs. Much more practical than a 911 or other sports cars.
Performance of the 2.3l E30 models isn’t as spectacular as their price tags might suggest. E36 M3 design is a bit bland. E46 had issues with rear suspension mounting points failing. E9x suffers from the same design issues as the regular models. All models have high-performance engines that require more maintenance (e.g. valve adjustment) and careful warming up. Known issues are rod bearing failures (both E46 and E9x), and throttle actuator failures (E9x).
Bare-bones E46 with manual transmission, in gray with black interior. It’s not for posing, but for driving!