'Haven’t tried the Kojak, so I can't comment on the tyre...But I am aware that manufacturers rationalise their product ranges from time to time. That is exactly how I started using the Stelvios. At the time, they were the only affordable 17 inch tyre I could find! I don’t know whether all these tyre are available to US customers, but the German Schwalbe website
http://www.schwalbe.de/gbl/en/homepage/ is worth a look. The Marathon now comes in 10 varieties, but I can’t find the Stelvio in any size…