Im using unibox to compare performance between the Tempest and the Dayton DVC 15". Im having probs. with excursions.i get like 30mm ONE WAY excursion @ 30hz when powered with 250w (Going to use 250w plate amp). Im i supposed to use 125w instead because their are two voice coils? So far im leaning toward a vented Dayton sub. Any reason why i should choose otherwise?