Brad.....just do it son! I finally got mine properly mounted and it's rock effin' solid. I utilized my stock jumpseat threaded holes in the rear "bump" of the cab. Threaded in some all thread, marked my holes, drilled 'em, tossed the box back on and threaded the nuts and washers on. I used 1.5" washers sandwiching the MDF. Now I know you don't have a 4dr like me, but I'm sure you can take some ideas from me and utilize it on your 2dr gen3. Here's a quick snap-shot....
[edit]: So photobucket is down....so I'll just attach my pic below. As you can see, I can barely use the rearmost hole....didn't plan it out perfectly, but the thing is really really solid. And using torx head wood screws adds some more security as well...
Take a peek at Brandon/Mb128's thread linked here:
http://www.fordrangerforum.com/vehic...love-subs.html
I'm not a big fan of it(I would've made it alot cleaner looking), but it shows how he mounted his to his back wall.