What are attachments in trunk?

I have recently purchased a '95 E320. I've had some rear stereo speakers drop their sound when hitting some hard bumps recently, so I decided to look around the trunk and how things are installed. The car has a MB CD changer in the trunk, and a factory phone. I was wondering exactly what a couple of the things are that are mounted in the trunk. I couldn't get all the trunk liner material out, so I could not see exactly what they were connected to. They are:

1) There is a bracket mounted in the trunk depression in the left rear corner that houses a box that has a coax(?) cable and another fairly thick cable connecteded to it.

2) There are two metal boxes (approx. 6" x 6" x 1") that are attached to the wall of the trunk next to the right wheel well. Both have a electrical harness connected to them.

I'm guessing they are probably phone related and stereo amplifier. Am I right? Which is which?

Thanks in advance.

The unit in the left rear is for the phone. It is the transmit and receive unit. The units in the right rear are the audio amplifiers for the sound system. They should be silver and be mounted opposite each other, up/down.
Enjoy the new ride,
turbo herb