If you said that the ultimate 911 is not necessarily made by Porsche, most people would raise an eyebrow. However, if you're in the know, there's a good chance you would immediately think of our guest this week: Alois Ruf, head of RUF Automobile. Combining maximum performance, personality and the very highest standards of German automotive engineering, RUF has been operating in its modern guise since the 1970s, with a long family history before that. Having boasted a number of the world's fastest production cars in its lineup over the years, and with its vehicles loved by sports car enthusiasts the world over, RUF is the very definition of a cult car manufacturer. We spoke to Alois about the legend of the CTR Yellowbird, life at RUF, and what he thinks is most important in a modern sports car...