The BMW M6 is a high-performance version of the 6 Series marketed under the BMW M sub-brand from 1983 to 2018 (with a break from 1990 to 2004). Introduced in the coupe body style, the M6 was also built in convertible and fastback sedan ('Gran Coupe') body styles for later generations. An M6 model was built for each of the first three generations of the 6 Series. Production of the M6 ended in 2018 and it was replaced by the BMW M8 (F91/F92/F93) in 2019. E24 M635CSi/M6 (1983–1989) The M6 lineage began in 1983 with the M635CSi model of the E24 6 Series range, which was powered by the M88/3 DOHC straight-six engine (which was a modified version of the engine used in the BMW M1 supercar). In most countries, the model was badged the M635CSi, however the equivalent model in North America and Japan was simply badged in "M6". The European-specification M635CSi used the M88/3 engine (without a catalytic converter), which generated at 6,500 rpm and at 4,500 rpm. The M6 version, sold in North America and Japan, used the S38B35 engine (with catalytic converter), which generated and at the same engine speeds. The catalyzed engine was also used in European and other market cars beginning in the summer of 1987, with identical specifications to the federalized engine. The sole transmission for all models was a 5-speed Getrag 280 manual transmission. Other changes included BBS RS wheels, a rear lip spoiler, a larger front air dam, larger front brakes and revised suspension with a lower ride height. The E24 series became a "world car" for the 1988 and 1989 model years, sporting the same bumpers and aerodynamic treatments as its high-performance counterparts across all markets. Production of the E24 M635CSi/M6 ended in 1989. According to BMW, the car can accelerate from in 5.8 and 6.8 seconds for the European and North American versions respectively. The curb weights of the 1987 models are for the M635 CSi and for the M6. A top speed of made the European M635CSi the second fastest BMW automobile ever built next to the M1. The quarter mile time for the M635 CSi has been recorded at 14.5 seconds while is achieved in 15 seconds. A total of 5,855 cars were produced. Of these, 1,677 cars were imported to North America. Due to the elongated front and rear bumpers, the length of the U.S. models