You'll want to comprehend and understand EVERYTHING about your Mercedes
Service/Upkeep "Jobs" before ordering parts or attempting repairs.
Do Not Even Dream of "Winging It" on the quality of parts or procedures!
Here's your reading lists for those long Summer Nights:
http://www.peachparts.com/shopforum/search.php?searchid=4847325
A Bonus! :
http://www.w124performance.com/images/