Subwoofer Box quesiton need suggestions!?

Just ordered (2) 15 Kicker L7 dual 4 ohm woofers... gonna be wired to a Rockford Fosgate T2000.1bd...kinetic 600hc in trunk...yellow top up front...220 amp alternator...Pioneer Priemere 9800 series..gonna be puttin them in a 1999 grand prix gt. There is a local audio shop who will make a box for me and he said he will have it set up for rear firing and be ported. Another shop that is a little farther and will take more time to get done says they will have them firing foward and seal off the box from the trunk so the only air being moved is in the vehicle itself not the trunk..the port would also be facing foward. My question is which would be a smarter application when it comes to being louder not only Db wise but also seeing and feeling in the vehicle?