1) go to home depot
2) go to the fencing hardware aisle
3) buy some 16ga Galvanized L brackets (they usually come pre-drilled with 4 holes in them)
4) go to fastener aisle, buy 1/2" long self-tapping screws, and 1" long wood screws
5) measure and mount L-brackets into floor of trunk
6) slide sub box between brackets
7) attach box to brackets via wood screws
8) box is not going ANYWHERE, and unless someone brings a power drill with them, that box is likely to still be there if you ever get ripped off.
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-Thomas-

2003 Redfire Cobra - 448whp/435wtq
1990 Eclipse GSX - possibly For Sale (Will fund cobra's clutch and IRS mods!)