Thanks for the replies guys!

I screwed up my description. It's on the DRIVER'S SIDE, not the passenger side like I previously stated. I was thinking about something else on the passenger side when I wrote this post. This sound is on the driver's side. Sorry 'bout that.

Man, seems like we always find the same issues with our cars and we end up all having the same or similar resolutions if any! Ha, it's funny because I've read and heard many auto journalists rave about this particular Mercedes engine, especially the hand-assembled version. They talk about how refined it is, how smooth it is, and how tough it is. I'll betcha if this was an American-built engine, they'd say it is noisy, makes unusual noises, and is a little un-refined! Well, it is smooth, powerful, and hopefully will last forever like many Merc engines do, but man, it seems like I hear a new, puzzling, annoying, and worrying sound every time I drive the darn thing. It groans, stumbles, and ticks, but goes like snot! Maybe it's just too quiet, maybe I'll just put a perf. muffler on it so I don't have to hear the squirrels knocking around in their cages anymore!!

On a serious note, I wonder if it's a pump, or some kind of solenoid that lives on that side of the car. Why would we all have the same sound on the same side of the car unless it is supposed to be there? Hmmm, some of the other noises could be due to the fact that there are 12 spark plugs firing off too. Could be coil noise, or arcing, or who knows what. German cars have always been known for quirks, and this one definitely has some. I'll just stop worrying about it and drive it until it dies either by old age, or by launching through the block. "Hey, why does your car tick and make all those noises?" "I don't know, I guess the pistons are starting their NASA organization!"

Really, if anyone finds a solution or a cause of this noise and others, let us know! The elec. tape on the hatch latch bar was brilliant!!