If it is really that chest-pounding, at-the-movies feel that you are looking for, then ditch the current sub and get a big-boy sub (or a pair

)from SVS, Rythmik, PSA, Outlaw or HSU.
The DTs are nice, and for most 2 channel music they should have plenty of bass. If you are into HipHop or Electronic music, they may not have enough bass to suit your room and listening habits. But there is no way these are going to compete with the clean, undistorted SPL of dedicated subs from one of the mentioned companies.