Clunking in the Rear

[vu 6thgen]

Hello, there is a loud clunking noise while I drive. I decided to take a video of my car stationary and me pushing the rear up and down. At first I ignored it but, it is getting really annoying :|
*Excuse the birds chirping and the squeaks (sway bar needs lube).
*Might have to turn volume up to hear the clunking.

Any help is greatly appreciated, thanks!

 

[Dinzdale40]

check the center nut on the top of the coilover from the inside where the rear seats are.....also check the endlinks

basically anything you took off or loosened when installing the coilovers