You dont seem to be really understanding what people are telling you. 15's are just not a feasible option. If you wanted to run just 2 15" subs in that trunk it would literally require the ENTIRE trunk being used as a box. It would require the box to be built and assembled in the trunk. My Ford Fusion has about that same amount of trunk space and i have a single 15" sub. I cant stand that i dont have the room to make a box that would allow the sub to maximize its potential. It also ***** that building the box out of the car severely limits the size you can go. I suppose to could go 2 sealed 15's but than your budget on an amp needs to go up significantly.