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 255 km/h (158 mph) 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 250 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 283 km/h (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.