560 SEL Timing Chain change

[hbofinger]

Hi -

I am contemplating a timing chain change on my 1989 560 SEL with 98,400 miles. I have been reading the posts here and am confused as to what to expect. I know from the service manual and from the posts here that I can do the change via the valve covers, i.e. no need to remove the timing case cover. However, will the guides on this model be plastic or metal, i.e. besides the timing chain, the valve cover gaskets, and the tensioner, what other parts should I purchase on the web before I get started? And am I being paranoid changing the chain now, or should I wait 20,000 more miles? The car is mint otherwise....