Are you asking about the 300D?
First, do you have any maintenance records from the previous owner(s)? Next, I wouldn't needlessly spend money replacing stuff that isn't worn out. Sure, it's easy to guess at things like, timing chain, motor mounts, valve adjustment, alternator brushes, transmission fluid and filter, air filter, engine oil and filter, fuel filters, etc, etc...
If you don't have a clear owner maintenance history on the car (or even if you do), the first thing I would do is take it to the best independent Mercedes mechanic in your area, and pay to have them do a pre-sales inspection (yes, I know you already bought the car...).
The hour or so labor is an excellent investment, and may tell you things that you hadn't even thought of, and will keep you from spending money on stuff that doesn't need doing instead of fixing what is really in need of repair and/or maintenance right now that you might've missed otherwise.
Then, get back to us and ask questions based upon the evaluation of your mechanic, if you need to.
[Edited by longston on 02-18-2001 at 11:02 PM]
"We drive into the future using only our rearview mirror."
- Marshall McLuhan -
Northern California Wine Country...
"Turbos whistle, grapes wine..."