Unfortunately, this will not work. Trunks are not acoustically sound nor selaed and will not be able to be used as an enclosure. The only way the idea can work is if you get a sub that specifically states "free air woofer" or "infinte baffle" . If you get a woofer with that specification then the idea of mounting the subs to a piece of MDF with no difinitive acoustical chamber (trunk) will work...