The BMW M3 is a high-performance version of the BMW 3 Series, developed by BMW's in-house motorsport division, BMW M GmbH. M3 models have been produced for every generation of 3 Series since the E30 M3 was introduced in 1986. Upgrades over the regular 3 Series models include engines, handling, brakes, aerodynamics, lightweight materials and various interior upgrades. The E46 M3 is powered by the S54 inline 6-cylinder 3. 2 liter. As with most M engines, the S54 has individual throttle bodies for each cylinder, with electronic throttle control (drive-by-wire) operation of the throttles being a new feature for the S54. Backing this S54 engine is the SMG which stands for Sequential Manual Gearbox. It's essentially a transmission capable of functioning as an automatic or functioning as a manual transmission. The innovation is that, when functioning as an automatic, the driver does not need to operate a clutch pedal, simply designate desired gear. This is done by a traditional stick, or a set of paddle shifters attached to the steering column or steering wheel, depending on the model BMW. While automatic mode is more fuel efficient, manual mode provides greater engine performance while removing...