Need advice

[dcofer]

I am going to be designing and building a box for my friend in the near future and wanted to get some advice before I did. The box isn't the hard part but its the install that im not sure about. I will be putting a 15" L5 in the back of a 2008 civic SI and I was planning on facing it forward and sealing it off from the trunk, so sub forward port forward. Is there anything specific I need to do to the trunk opening to secure the box? I am assuming I can build a frame and bolt it to the metal wall edges with some foam between to eliminate vibration, then just have the box screwed to the frame. Does this sound like a good approach? also I doubt the sub will be able to stand vertical (but it might, the trunk is 1.5 hours away so i cant measure) so also would it matter if I angled the sub up or down? The box will probably just be built to specs since space is an issue (though I hoping I have enough space to modify it hehe). I am not a metal worker and do not plan to do any modification to the car itself aside from drilling and bolting. All advice and tips are greatly appreciated.

[jeyrapboy]

When i did my buddy car all i did was use L shaped brackets on the back of the box.

Then made trim panels and spray foamed it to seal it off.