You would need to consult manuals, and compare a 1999-2003 SLK320 (which is very similar to Crossfire) to your own car. Wiring could be the same, but hard to tell for sure. Accessories are probably similar, but power steering pump is likely different. I doubt you'll find much help here on the E class, but benzworld or mbworld might have more knowledge of the R170 -> W211 swap.