check this link out. its got the step by step guide. http://www.fitaudio.com/?View=entry&EntryID=157 However if your looking for how to do it on the 2door coupe version like myself, well im still looking lol...
The 2004 Mercedes-Benz M-Class has a V6 engine.
The 2004 Mercedes-Benz C-Class has 16 valves.
The 2004 Mercedes-Benz G-Class has 24 valves.
The 2004 Mercedes-Benz E-Class has 18 valves.
The 2004 Mercedes-Benz G-Class has a V8 engine.
The 2004 Mercedes-Benz CL-Class has 24 valves.
The 2004 Mercedes-Benz CL-Class has a V8 engine.
The 2004 Mercedes-Benz SL-Class has a V8 engine.
The 2004 Mercedes-Benz S-Class has 24 valves.
The 2004 Mercedes-Benz SLK-Class has 16 valves.
The 2004 Mercedes-Benz M-Class has 18 valves.
The 2004 Mercedes-Benz SL-Class has 24 valves.