Planning spring build. Sub suggestions needed

[chunt33]

Here is the deal. I have a 02 chrysler concorde. Unfortanetly, the seats do not fold down, however there is a armest that folds down with an opening 8x8 inches. Im planning on glassing the rear deck and back seat leaving the square open. Then, using a 6th order bandpass i plan on sealing the box to the cabin (having part of the port be external to the box). Currently, I have 2 sundown 2500s sittin in my closet, and come spring I will have sufficient electrical. I was leaning toward 2 12s due to the fact that it is a trunk car, however due to the fact that that im sealing it I wonder how you guys think an 18 would perform. My current ideas include 2 DD 9512s, 2 DC XL 12s, 2DC Lvl5 (for possible future growth), 2 SSA Xcon 12s, or maybe something like 1 TC sounds lms ulta 5400 (18). My goal for the build is not necessarily a high SPL number, but more ear loudness with decent sound quality, and I love the lows. I wanna know what your thoughts are on my current sub ideas, and am also open to other suggetions. Also, if you think my 6th order idea is bad let me know, but I was planning on letting PWK design it for me because he is the man .

[chunt33]

Figured I would throw a poll up here to make things a little easier.