I have done this on a 500E...If the oil changes are neglected EVER, or if the chain tensioner rattles even the slightest on start up, I'd have this done.

You will need the rails, tensioner, and a new chain. ( This is how we do it and we have had no problems)

Specail tools are required, be sure the shop has done this before.

------------------
Benzmac:
Donnie Drummonds
1991 GMC Syclone
ASE CERTIFIED MASTER AUTO TECHNICIAN
SERVICE MANAGER FOR 14 BAY FACILITY
MERCEDES SPECIALIST 8 YRS
PARTNER IN MERCEDESSHOP.COM