Stereo install

It's cool that everyone has different ideas of how this could be done. My 2¢ worth would be to carpet it with no visibile seam where the carpet would transition from the floor to the bulkhead. The carpet would be more sound absorbent and take more abuse from things being tossed into/around the back of the interior.

Seeing the color of your avatar, have you considered going with copper colored carpeting and cream colored seats & door panels? Got a Bentley at work with that combination. Very cool.