ok so i designed a system for my 1 friend he has a 1990 sumthin astro van an i was thinkin 4 12inch kicker cvrs in a 17 cuft box each sub havin there own 4.25cuft box slot port tuned @ 26hz with there own 3 inch wide slot port an it facin up @ the roof but i dunno what kinda amp was thinking of a hifonics or 1 kicker 1200 or if any1 nos whats the spec. port tune an let me kno what kinda amp will do price under 400 or cheaper thankx it should slam when i get th e box done