17. BMW 320 Si E90
BMW was quite busy in early 2000 when it came to racing. Formula One, GT championship, and ETCC series were all dominated by BMW racing teams. However, for the Touring car championship, BMW needed a homologation special and that is how the E90 320 SI came to be. It looked like any other E92 sedan from the outside, but under the hood, a 2.0-liter four-cylinder engine was a true racing gem (via Collecting Cars).
Even though it sounded cool, the 320 Si repeated the same mistake as E30 M3 – putting a racing engine into a road car. To start, BMW Germany never produced this engine, and the N54B20S was assembled in the UK by a specialized engine shop that made Formula One engines. It means that this engine was hand-built from the finest and most advanced materials, but this didn’t help the reliability. Interestingly, the N54B20S came without BMW’s signature Valvetronic system since it limited the rev capacity of the unit. The result was 175 HP with 147 lb.-ft of torque which was pathetic. BMW made only 2,600 cars, and almost all suffered fatal engine failure at some point.