In 2003, from June to December, BMW made 1385 CSL versions of the E46 M3. CSL stands for “Coupe, Sport, Leichtbau”, hinting that BMW had designed a car even faster than the standard E46 M3.
Obviously, it is not easy to improve on an E46 M3, as it already has all the major BMW M features. Therefore, the CSL has small improvements, but lots of them:
1) CSL is lighter
2) CSL has more power
3) CSL has suspension and steering upgrades that improve handling
4) CSL has improved aerodynamics
5) CSL has better grip
All those small improvements together amount to quite a significant performance increase. At the Nürburgring, the E46 M3 has clocked a very impressive lap time of 8:22. The CSL has a time of 7:50. That is a night-and-day difference.
As part of the extensive weight saving program, some equipment was simply left out. There is no navigation, sunroof, fog lights or leather seats. In fact, the car could even be ordered without air-conditioning and a radio, both being quite heavy items to drag around a race-track. And where it really counts, some parts were replaced by much more expensive lightweight items, such as the wheels, front apron, roof, bootlid, rear window and front seats.
To further improve the performance, engine power was increased to 360hp, which is 17hp more than in the standard E46 M3. Suspension, steering and brakes were upgraded. Front splitters and a redesigned bootlid were included to reduce aerodynamic lift. And to perfect the masterpiece, semi-slick Michelin Pilot Sport Cup tires were the choice.
BMW still wanted, however, to maintain the everyday usability of the car, so it continued to have some equipment that many sports cars don’t, such as rear seats (that even fold for extra storage capacity), power windows and mirrors, and reading lights for 4 people!