What would ya charge for an enclosure design? Current setup is an 08 hhr ss with 300 amp alt, 2 agm's, about 500 rms between doors on timpano mids, 3k rms on skar zvx12v2 d2's @.5 to get the 3k. Box is 5.4 cubes slot port at 34. Box built for american bass xfl and needs more port area cause I...