BMW E24 M6Information courtesy of the M Registry History What makes the M6535CSi/M6 unique? The M635CSi and M6 are the BMW Motorsport-developed versions of the E24 6 Series coupe and are powered by twin-cam, 24-valve inline-six-cylinder engines known as the M88 or S38, which were both derived from those used in the M1 sports car. They also feature a revised chassis and several unique cosmetic items. What’s the difference between the M635CSi and M6? All examples of the BMW Motorsport-developed E24 6 Series coupes are officially designated as the M635CSi. However, in both North America and Japan, they were known and badged as the "M6", both to simplify the name and to bring it in line with the other M models, specifically the M3 and M5. When was the M635CSi/M6 first introduced? The M635CSi was introduced at the 1983 Frankfurt Motor Show. Where was the M635CSi/M6 built? Like all 6 Series, the M635CSi/M6 was built on the normal Dingolfing assembly line, with body shells shipped from the Karmann works in Osnabruck.