Looks pretty good, do you already have a deck? I would just buy the subs and box complete, like this...
http://cgi.ebay.com/KICKER-08-DS12L7-12-L7-SUB-WOOFERS-S12L7-ENCLOSURE-BOX_W0QQitemZ220439645134QQcmdZViewItemQQptZCar_Subwoofers_Enclosures?hash=item33533a0bce#ht_3923wt_1165
Since that is...