In another post , it claims to improve fuel economy, ive had my car for 80K perosnaly i dont rember once doing it.
How does one do it is it hard?
btw, I have a pritty good understanding of my 300SD so far...

Its not hard to do and it is easier if you get the special wrenches (~$75). You should have a .003" and .005" feeler gages for go and nogo for the intake valves and a .013" and .015" feeler gage for go and nogo for the exhaust valves. Make the .003" and .013" gages are completely loose and the .005" and .015" gages won't go. You also need a 27mm or 1 1/8" deep socket and a ratchet to turn the crankshaft. Turn engine clockwise only (facing car).

Replace the valve cover gasket to prevent leaks. Check the timing chain wear also. It should not be more than 3 degrees off on the flywheel damper when cam timing marks are lined up. Make sure the chain tensioner is working properly.

P E H

PS: Try spell check.