Its even hard to answer...they are simply completely different cars.
The SL class is basically a sports car..2 seater configuration...performance minded, originally styled as convertible (although frequently having a hard top too).
The CL is originally a 4 or 5 passenger sedan.
Mercedes-Benz CL-Class was created in 1998.
The 2009 Mercedes-Benz CL-Class has 32 valves.
The 2010 Mercedes-Benz CL-Class has 32 valves.
The 2008 Mercedes-Benz CL-Class has a V8 engine.
The 2006 Mercedes-Benz CL-Class has a V8 engine.
The 2007 Mercedes-Benz CL-Class has a V8 engine.
The 2011 Mercedes-Benz CL-Class has 32 valves.
The 2011 Mercedes-Benz CL-Class has a V8 engine.
The 2004 Mercedes-Benz CL-Class has 24 valves.
The 2014 Mercedes-Benz CL-Class has 32 valves.
The 2004 Mercedes-Benz CL-Class has a V8 engine.
The 2009 Mercedes-Benz CL-Class has a V8 engine.