Hi all I have 2 12" subs in a home made box and i was just wondering how i can bolt it down in my trunk????? I cant even hit the gas a tiny bit without sending the box into the back of my trunk..I also hate it moving cuss i continuasly have to put the floor mat back in place. I was going to bolt it into the trunk but theres this black box on the under side of the car right where the bolts would go!!! what is that?? and is there any other options other than bolting??? Thanks to all who reply!!!