i have a 2006 dodge charger and here are my max dimensions for a...
this is if i put 2 boxes, the reason for this is because the opening of my trunk isnt that big, but the trunk it self is a decent size, this is the max dimensions total..
here is an idea i had, i have a vent that is about 24in x 10in in my rear deck
feel free to add on to this or totally change the idea. also, i have no tuning or anything to this rought draft so please provide exact measurements and tuning.