Thanks for the polite dope slap on the bushings. I understand.
The tensioner is being replaced because I have been told in the past that MB techs are trained (?) to listen for the tell-tale rattle that a timing chain makes when it needs replacement. Believe it or not, that was an MBUSA official reply to the question of when do the chains need replacement. According to the Tech Rep, MBUSA assumes regualr maintenance is performed at an authorized dealer and the technicians will identify when the chain is starting to make noise because it is an obvious sound. I have a noticeable rattling sound on startup after the engine has been off for over 24 hours that sounds more like a chain than lifters and appears to be from the front of the engine. The sound is never really loud but I notice it and my wife has even commented on it. It goes away after 15 seconds of idling, then it will be noticable again when the car is slipped into gear and the idle drops (oil pressure drops).
If I'm dong something unnecessarily, I don't think it will harm anything.