I recently purchased 2009 (only 35K miles!!) and after a couple of days noticed the rattle that seemed to be coming from the side pillar just behind my left ear. Through a long process of elimination and with the help of my 14 year old daughter we located the source of the rattle and killed it!! It turns out it is not in the pillar but on the inside of the door. There is a hard plastic stop on the end of the arm that keeps the door from opening too far. When the door is closed (and the arm is fully enclosed inside the door) that stop can become loose and bounces around on the metal arm at certain speeds or when going over bumps in the road. To get to it you have to peel back the white covering from the top right of the door so you can expose an area big enough to get your arm in to. With the door closed you can find the plastic piece just inside the edge of the opening. I wrapped that piece in duct tape, also making sure some tape made it onto the metal arm and bingo...no more rattle. Prior to this I added foam pieces in all the door trims and the panel but the rattle would always come back. That also explains why the dealers haven't been able to stop it as all they do is add foam to the inside of the panel. Hopefully this helps anyone who has posted that they have the same rattle and were not able to find the solution. It was highly annoying being that it was right behind you while driving. Good luck!!