BMW added a new coupe model to its range in 1976, the 6-Series. The 6-Series initially comprised of models powered by a range of straight six engines which included 2788cc, 2935cc, 3210cc, 3430cc and 3453cc units. This range was reduced to just two options, the 628i and 635CSiA during the 1980's.
In 1985 the ultimate development of the 6-Series arrived, the M635CSi. This new model featured a special M Technic body kit, alloy wheels and special interior trim. The M635CSi developed a mighty 286bhp which gave it earth shattering performance. Production lasted until the 8-Series arrived in 1989.