The E24 6-Series matured over its ten years in production into an extremely capable grand tourer, the elegant styling by Paul Bracq complemented by a luxuriously appointed cabin with typically well thought out ergonomics. New technology abounded, the Check Control System monitoring brake pads, lights and fluid levels plus a trip computer. In June 1978, a more powerful 6-Series - the 635 CSi - was announced with the largest six available, the 3.5-litre unit developing 220bhp significantly improving performance levels while the optional ZF automatic transmission had three different modes. The new 635 CSi was distinguished by a front air-dam and boot lid spoiler to improve down force. The body shells were completed to a high standard by Karmann of Osnabruck, who were also responsible for assembling the 6-Series in their first year of production. The 6-Series may have been a more refined and relaxed GT car than the CS it replaced, but it was still developed into a very effective track car, winning the 1983 European Touring Car Championship and acquitting itself well in Australia during the Group A era, with drivers like Jim Richards hustling the black and gold coupes around Bathurst to good effect. In total some 45,213 CSi 635 BMWs were built between 1978 and 1989 but decent examples left in Australia would be a tiny fraction of this number and prices can only get stronger as these coupes reach classic status.