Considering a r320
 

I’m looking to replace my 1983 300d (361,000 and climbing) and am considering an r class, likely an early model, and probably with close to 200k. Am I crazy? Can they be worked on without buying lots of diagnostic equipment? What are the major issues to look out for when test driving? Are there any complicated “must do” maintenance items? (Timing belt/chain, etc) I tried finding a maintenance schedule, but the website listed changing spark plugs which I found odd and disconcerting on a diesel.

I've had my R350 for 6 years and about 80,000 miles. I am the third owner and had my indy do a PPI before I commited to purchase. They were familiar with it as the PO had had it serviced with them. The only issues I've had are front shocks, rear air bags and a power steering reservoir leak. One electrical gremlin is my side marker light coming and going.
It's got a ton of room inside, it'll swallow two eight foot kayaks with the seats down. I'm actually thinking of moving to a newer one, 2011 or '12. They aren't that popular so prices are pretty good. I'm not sure about the diesels but the gas engine gets a solid 19 mpg (US gallon) average.