The man who presided over the most controversial chapter in BMW performance car history has left.Dr Kay Segler was Mini boss from 2004-08 and now returns to that position after leading the M-division for the last three years. Under Segler’s management BMW’s hallowed M-division has done all manner of things to its products that they promised theynever would, including the first all-wheel drive M-cars, first M-badged SUV's and first autoc transmission M products. There is the little issue of Segler telling engineers to add forced-induction, too.Ironically, all four of these anti-M-heritage engineering features debuted on a single line, the X5/6 M models…SAVIOUR OR SIMPLETON? After his three years at the helm Segler has been vilified by BMW traditionalists for basically ensuring that the M-division will never produce another naturally aspirated car. Industry analysts see things quite differently. They believe Segler secured a future for the M-division’s values of performance and engineering excellence by forcing a significant change in mindset upon engineers and product planners operating at BMW’s Garching facility.Segler now returns to Mini, and from Mini comes his replacement - the rather interestingly named Dr Friedrich Nitschke, former head of Mini's product planning.In the minds of M-division fans the question is simple: Can this man Nitschke lead M-division design smoothly through a future of pending existential crisis regarding its position in a world of ever-tightening environmental regulations?