I'd agree with 110Nm for the SLK, though not convinced with the CLS.
Mine (E Class) is 130Nm according to the handbook, and a quick online check leads me to believe this is the same for the CLS as it's basically the same underpinnings.
150Nm for my 2009 CL 500 (C216). According to the manual page 381 "The wheels could work loose if they are not tightend to a torque of 150Nm". So that's 110.6ft/lb.