Personally, I would keep the 15W3 ( helluvasub ) , make sure its in the right box (around 2.25 - 2.5 cubic feet sealed) and hit that sucker with a good Class D subwoofer amp, like a JL 500/1 or more. That sub CAN handle some power. Get it up under the rear deck and fire it BACK. An enclosure with the proper airspace for that particular sub will be too big to go anywhere else. Don't be afraid to hit that puppy with alot of power, it will handle it. With the excursion capabilities of that sub and alot of power... that thing will rattle your sphincter like you won't believe
