OK, so I finally got time to find that annoying rattle from the rear of the shelf by the speakers.
This info is for coupe owners so I have no idea if it will work with sedans.
To test if you have the same problem as mine, fold down the rear seat, open the trunk and hit your fist at the center base of the glass where it meets the trunk. If you get the rattle/buzzing noise, here's your fix!
Pull out the 8 push pins holding the liner in, pry gently down on the liner, mine had a couple peices of double sided tape. In the center of the trunk top you will see this little white clip that apparently holds down the tray from above.
Push up on the clip while hitting the glass again.
Gone? Great!
I used a small piece of wood to add pressure to the clip as well as a piece of rubber wedged into that hole to push up on the shelf.

One more annoying rattle gone!

 

im getting a very annoying rattle from the rear deck close to the passenger speaker, was yours from that side?

 

Yes.
Pound on the base of the glass to verify.

 

i just tried and it didn't rattle mine is coming more from the passeger side speaker like at the end of the deck but thx though, if ever that rattle will come i know wat to do thx man

 

i have the same problem on the passenger side...any fix?