Yorb wrote:plus i think insurance wont cover it of it aint bolted down.
Never heard of that... but bolting your hardware down is a good idea anyway.
If you check your owner's manual, you'll see there are two bolts in the floor of the hatch (about 6 inches from the back) on either side designed to hold child safety seats. These are ideal: bolt a plank of wood to the two of them and then use L brackets to secure your box to the wood.
If you are creative enough, you can actually get the wood and brackets hidden (for the most part) by the carpeting.
http://masticatingcow.nismo.org/install.html
Here's a link to how I bolted in my old bandpass 10 x 2 box. I've since upgraded to a slotted 12 x 1, but hopefully it'll give you an idea of what I'm talking about.
EDIT: Nismo.org doesn't like hotlinking, so the link above is to a dummy page. Be sure to click on the "CLICK HERE" link... located just under the junk banner on top.