sub help!

hope to get some inputs for the sub. it could be a 12" or 15". car to be designed on is a 96 accord. target is to be able to play loud but accurate. meaning it can play rap, techno/trans, soft/ballads, rock etc., still with good readings from termlab... possiblly dbdrag style yet as accurate sounding as possible.

requirements:

1. box is no bigger that 3.5 cubes - so that spare tire would be accessible

2. box design can only be a wedge 2 enclosure type box - to maximize all space and still get the spare tire

3. sub would be placed facing the cabin, possibly on the back seat position for a single sub, but towards the trunk for a dual sub or all towards the trunk. depends on your design.

4. ports can only be round ports

5. round ports are place on top of the rear dash extended to the box. - ports cant be place beside the sub for the purpose that atleast 2 people can still sit on the back, one on each side of the sub ("assuming sub is placed towards the cabin").

6. power would be flexible for the amp is not yet bought. could be 1500-2000 watts in 1 ohm

box would appear as if rear dash is the top of the box and the back seat be the front face or rear of the box.

is there a sub that would fit the requirements? what model? can that be the level 4?

TIA