I want to get a box to plug into the back of my headunit. I want to install (read screw in) it on the hump separating the foot are of the back 2 seats... directly behind the console. So I have 2 questions:

1. Is it ok to screw the box in at that position?
2. How do I get to the back of my headunit... and what tools will I need?

The box is a Sony XA-300, if that makes a difference.

Any help is much appreciated! Thanks ladies and gents!