I got a 12" autotek meanmachine.
It was cheap but it sounded good in my old box. I'm not trying to blow my hatch glass out by any means.
It's got a mounting debts of 5.5" so I might adjust the depth of the box to give more hatch space. It only sticks out past the opening by about 4-5".
“Who you are speaks so loudly I can't hear what you're saying.” -Ralph Waldo Emerson.