A high performance variant of the produced by BMW 3-Series beginning in 1985.
The following section is an excerpt from Wikipedia's BMW M3 page on 24 September 2018, text available via the Creative Commons Attribution-ShareAlike 3.0 Unported License.
The BMW M3 is a high-performance version of the 3 Series, developed by BMW's in-house motorsport division, BMW M GmbH. M3 models have been derived from the subsequent generations of the BMW 3 Series.
The initial model was available in a coupé body style. At times the M3 has also been available in saloon and convertible body styles. Due to the coupé and convertible models no longer being part of the 3 Series range from 2015, the F82/F83 coupe and convertible models are now called the M4 based on the newly introduced 4 Series. The M3 name remains in use solely for the saloon version.
Upgrades over the standard 3 Series automobiles include more powerful and responsive engines, improved handling/suspension/braking systems, aerodynamic body enhancements, lightweight components and interior/exterior accents with the tri-colour "M" (Motorsport) emblem.