BMW E46 M3 was unveiled as a show car at the Frankfurt Motor Show in September 1999. Six months later, it celebrated a world premiere at the Geneva Motor Show. The third M3 was very powerful, wide and yet elegant. Thanks to a special front apron with integrated fog lamps and large cooling air intakes, it presented a significantly different profile to all other models in the BMW 3 Series. The engine compartment lid made of aluminium was curved in the centre, forming a power dome to create space for the M3 engine. The side profile of the M3 body including the wheel arches had undergone an increase in width of 20 millimetres, with air intakes and M3 badge in the front side panels. This beefy appearance was a visible consequence of aerodynamic optimization and an attribute creating a profile distinct from that of the 3 Series coupe. It was accompanied by appropriately beefy wide wheels in the format 225/45 ZR 18 at the front and 255/40 ZR 18 at the rear.
The impressive visual appearance of the M high-performance athlete was underscored by aspherical M outside mirrors, side sill trims and an aerodynamically optimised rear apron with rear spoiler lip. Any driver who was still unaware of which car had overtaken them was left in no doubt when they saw the four tailpipes of the twin-chamber exhaust system that it was a member of the M family of automobiles. Sports seats developed in-house with outstanding ergonomic characteristics provided an impressive combination of lateral support and unrestricted capability for travelling long distances. Apart from the diverse electrical adjustment options at all levels, adjustment of the reclining width was also supplied as a special.
The heart of the new BMW M3 was again an inline six-cylinder engine, the classic BMW power unit. Like its predecessor, this completely new engine offered lots of torque, even more power and all this for relatively low petrol consumption and low exhaust values. The M3 engine generated the impressive power of 343 hp (252 kW) from displacement of precisely 3246 cubic centimetres at an engine speed of 7900 rpm. The maximum torque achieved 365 newton metres at 4900 rpm. This yields a specific power of 105 hp for every litre, a value that has only been achieved by a few high-performance sports cars in the world not fitted with a turbocharger.
The highlights of the engine included a friction optimised cylinder head with cam follower valve timing. The double VANOS variable timing familiar from the other M models was further optimised. Electronic throttle valve control was responsible for actuating the six individual throttle valves. It communicated directly with the MSS 54 engine control unit specially developed for the M3. This multiprocessor system had two 32 bit microcontrollers and two timing coprocessors and computing power of 25 million calculations per second. The BMW E46 M3 accelerated from a standing start to 100 km/h in just 5.2 seconds. It took this car just 5.4 seconds to accelerate from 80 to 120 km/h in fourth gear. A special switch, the M Driving Dynamic Control, allowed drivers to select between sporty and high-comfort engine response.
The engine’s power was effortlessly transferred to the road with the six-speed manual gearshift. The variable M differential lock being used for the first time in the M3 provided efficient support. Differential locks could distribute different levels of tractive force individually to the rear drive wheels, depending on which wheel had the best traction. The special feature of the variable M differential lock was that it recorded the different rotational speeds rather than the different torque of the left-hand and right-hand rear wheels as in conventional systems. The difference in rotational speeds was compensated by the limited-slip system containing viscose oil so that adequate forward thrust was provided. This system provided a locking effect from 0 to 100 percent. The chassis ensured outstanding roadholding. The engineers at BMW M implemented a lot of ideas to ensure that the car was capable of rising to the challenge of all types of handling limits: a high level of stiffness and minimising of the unsprung suspension components combined with a directness in performance unrivalled in this class. Lots of power also demanded excellent braking force. That’s why the M3 was given a robust high-performance braking system with floating compound brakes and perforated brake discs.