"In 1983 BMW took the M88/3 six-cylinder engine, a modified version of the M88/1 from the BMW M1 and put it in the E24 chassis of the BMW 6-Series, creating the M635CSi (called the M6 in North America). It was the only M6 generation having just a manual transmission as its only transmission offering at the time.
The M6 was critically acclaimed throughout its lifespan for its elegant, aggressive "shark-nose" styling, its luxury equipment, and its performance. A top speed of 158 mph (254 km/h) makes the European version the second fastest BMW ever built next to the M1. This is due to all other BMW models being electronically restricted to 249 km/h (155 mph). However, Rug Cunninham BMW ran a bone stock 1987 BMW M6 in the La Carrera Classic Race in Mexico in 1989, and reportedly recorded a top speed of 176 mph indicated. An M6 can be distinguished from other E24 models by a larger front air dam, a rear spoiler, BBS wheels, colour matching side view mirrors, M badges on the grille and back, and slightly larger front brakes.
In North America (United States and Canada), the E24 M6 was fitted with the catalyzed S38B35 motor, producing 191 kW (256 bhp) and 329 N·m (243 lbf·ft) of torque. The non-catalyzed version produced 213 kW (286 bhp) and 340 N·m (251 lb·ft) of torque. The non-catalyzed versions were only available in Europe, though there were 538 catalyzed M635csi models sold in Europe in 1988 and 1989. The 1988 and 1989 the M6 was a "world car" with the same bumpers and aerodynamic treatments in all markets.
The M6 achieved 0–97 km/h (0–60 mph) time of 6.0 and 6.8 seconds for the European and American versions, respectively.
Quarter mile times for the European version have been recorded at 14.5 seconds while 161 km/h (100 mph) is achieved in 15 seconds. However, Car and Driver Magazine tested the U.S. M6 in July 1987 and achieved a 0–97 km/h (0–60 mph) time of 6.1 seconds. Also in 1987 Road and Track featured the U.S. M6 as one of the 10 fastest cars in America. Production of the M6 ended in 1989, with 5,859 cars sold, 1,767 of which were North American (U.S. & Canada) models.