I finally heard a DD1508, and **** was I impressed. Impressed enough that now I'm thinking of buying some. Would 4 of these get louder to the ear daily, than a AQ HDC3 18? I have plenty of trunk space, but I was wondering if the little 8s could keep up with the larger sub. I'm either going 4cuft after displacement for the 8s, or 6.5cuft for the 18. Both will be on about 2000w for now, but going up to about 3000 down the road.