Cody, like Kyle said you can put 10's under the back seat but they will be small 10's with very little depth and magnet size, if you want bass and not just tunes to go with the music you’re going to have to do some kind of midgate replacement box. JL's box is nice but IMO the standard speakers that MUST be sold with the box are not what I'd want. So I support and am using Subthump midgate box. Details can be found here, just scroll down a little. It seems they are out of the box's right now but they always build more...
http://www.subthump.com/index2.htm You can try 10's under the seat. I did but it just was never enough no matter the subs that would fit...
Enjoy the new truck/suv!