04 grand marquis, 250 amp alt, big 3 done 1/0, XS 3400d under hood, cresendo 3500d, soundqubed 125.4, mb quart 80.4, 4 gauge wire going to the speaker amps fromk batt, 1/0 going to the sub amp from batt. lights dim pretty good at full tilt. gains are set correctly.