Boxchevyboi2785

Im in the process os starting my very first build, Im going to be going with DC (2) 15" lvl 5's , and a 7.5k amp. I need to know how big of a box i need to build to in my trunk so that 1, I get the best performance, and 2, I can still close my trunk. also in this mix I want to do a blow through. any advice on how I can get what I'm looking, or any suggestions on what I should do. as far as the box goes. I'm up for building a wall if that would be a better option. Just looking for advise/ info on what i should do. any help would be greatly appreciated.