I was thinking L-brackets and some shallow screws? It's a steel floor in the trunk of a sedan.

 

mine are secured in my truck with l brackets and 1/4 inch screws im pretty sure. stays put, so i'd say that is your best bet.

 

There are many ways! Just be inventive.

Hell, Kicker uses 4 Steel Straps with 3 holes in them, 2 countersunk holes for the box and one countersunk on the opposite side for the floor.

Ive seen everything from toolboxes to string to 2x4's on all sides to screws through the box.

So MAKE SOMETHING, just be clean about it.

 

i agree be clean about it.

if the L bracket works, mount it in the back and on the sides more toward the back. the sub will be still and you wont see the brackets.

but the more inventive you are, the better you will feel when someone sees it and compliments it.

 

duct tape just match it to the color of your interior and no one will notice let em know how this works i have high hopes for it :P