I have another question which may or may not have been answered elsewhere. I'm looking at subwoofer plate amps, and I'm leaning towards the Dayton Audio SPA500. Since your 3pi subs are carefully tuned to 20Hz, would you lengthen the cabinet to make up for the decreased interior volume caused by the plate amp protruding into the cabinet? Rough calculation (I'd get more precise for the real deal) on this amp would see approximately 400cubic inches of volume reduction which can be made up for by 1+ inches of extension. in one dimension of the cabinet.