you said your width is 31" how much space will that leave between the box and your fender wells? and what size...how many...aero ports are you using?
generally speaking you will get better response in the lower frequencies if you have something solid for the port to load on, i.e. the back of the trunk or the fender well. if you fire the port directly into the cabin you will still get decent response but not as good. Or you can tune lower and fire forward.
Also what type of music to plan to play and from what type of media?
