2006 impala
(2) level 5 12"s
(1) ab 1100.1 @ .25
(1) nsb3100 (trunk battery)
(1) d3400 (under hood)
(1) singer 350 amp alt
149.4 sealed on dash
147.8 on music average 30 sec door open
my personal experance:
i did a sealed box in a miata ... added poly fill and it made a world of difference freq response was much better then the empty box
shallow mount 6.5" kicker on a 200 watts or so
install a volt meter.. and if you drain the batts alot and offen make sure you charge them with a charger and not the alt... it will make the alt last longer ... but you should be fine