build a box that incorperates the space under the back seat as well as the storage area. or you can do what me and my friends did...get rid of the back seat.
--My truck: 2006 GMC 1500 crew cab, Kenwood DNX570HD, DLS front stage, JL JX1000.1, JL dual 8w3v3 microsub enclosure, Second Skin deadening.
--Wife's car: 2013 Chevrolet Impala LTZ, Kenwood DNX470, GermanMAESTRO components on CT125.2, 2x AT10"s on an AT800.1, RF Deadskin deadening.
--Work truck: 2014 GMC 2500 crew cab, Kenwood DNX470, Kenwood front stage, DD M1A on a pair of American Bass XD10s.