Well I got a new car, a 04 Corolla and now I need to build a sub box. I have already ran a DD 9515 forward firing in a taurus off a KX 2500.1 with the trunk seal off. It worked quite well with the seats down but with the seats up it lacked in output. I am now looking into putting in a 4th or 6th order (I doubt I have room for a 6th) with 2 6" ports through the 6x9 holes. I just need help with box sizes, I will probably have to build the box inside the trunk but I have from about 3.8 cubes to about 5.6 cubes to work with, I need bass that hits pretty low (I love Young Jeezy) and isn't too peaky. I will be going to college with the car so I want a bit of trunk space. Throw out some sizes that I could use that would work out and throw some comments out about putting a DD 9515 in a bandpass.