Going thru a few different sub enclosures. I think I came up with the design that will allow to run 4 of the level 6 18's... The enclosure will have the sub firing upward... Which worries me a lil cause of the room I have between the sub and trunk lid. Running my port on the side of the box facing inside the car... Now the enclosure will cut like .8 cft3 off each sub... This is just a thought still in process... Critic and criticize..but im not tryin to hear bs responses