I HAVE 2 PIONEER CHAMPION SERIES 12" 400 RMS EACH NEED HELP TO DESIGN A SUB ENCLOSURE IN MY MITSUBISHI LANCER CEDIA WAGON TRUNK SPACE BE D=27",H=29" AND W=51" LOOKING FOR AN L PORTED BOX IT IS RECOMMEND 1.5 CUBIC PER SUB IN PORTED ENCLOSURE AND HELP WOULD BE AN ASSET RIGHT DOIN MY FIRST BUILD