Wow, I didnt know of that problem before on the 420's.
I always though MB chains were reliable and rarely broke. The 84 300D turbo that I have just turned 100,000 a couple months ago, I took it to the dealer wanting to put a new one on but they said not to worry about it that it can go another 25,000 miles which is like eternity for a car thats never really driven and just sits in the garage all day.
My other two MBs have been pretty good with timing chain. So would you recomend more frequent changes in timing chain, like every 80,000 miles instead?