My honest opinion? Don't buy that box. It's a huge waste of money. For the same price or less you can build one that's actually spec for your subs and not tuned in the high 30's low 40's. It really isn't hard I build one. If you can't tho, it wouldn't be that much more to have someone else do it. I'm telling you now, you won't get full potential out of your subs with that box.
Also, you could measure your trunk lol