The 2021 BMW M3 CS is an upcoming, higher performance version of the company's four-door sedan. A successor to the F80-generation M3 CS that BMW produced in 2018, the 2021 M3 CS will boast similar upgrades over the current M3. It will feature a more powerful engine, a range of aero-enhancing features on the outside, some exclusive trim on the inside, and it will be built in limited numbers. Find out what will set it apart from the current M3 in the speculative review below.