Thanks, MBDoc. I swear the door hinges etc. always were a bit whiter from lithium grease when I brought into the dealer for maintenance.
One of the door lock mechanisms makes a slight groan noise when I open the door now do I figured it needed some grease.

As for the sunroof, I only tilt it and the only thing annoying is the rattle of the popup deflector mechanism. Too worried about bird poop to open it all the way ;-)